Anaconda Navigator don't launch since update to version 2.7.0

Product Help Anaconda Navigator
1

Yesterday the Anaconda Navigator recommended the update from version 2.6.6 to the latest version 2.7.0. I executed the update and after a while a message window informed me about the successfull update. The window presented a button for a direct launch of the Navigator. I clicked the button but the Navigator didn’t start.

Further actions taken so far:

Click on the Anaconda Navigator icon on the desktop: Navigator don’t start.

Restart of the computer and click on the Anaconda Navigator icon on the desktop: Navigator don’t start.

Inspection of the launch link in the properties of the Anaconda Navigator icon:
Here I found the following strange entry:
C:\Users\\anaconda3\pythonw.exe C:\Users\\anaconda3\cwp.py C:\Users\\anaconda3 C:\Users\\anaconda3\pythonw.exe C:\Users\\anaconda3\Scripts\anaconda-navigator-script.py
It seems as if the program “pythonw.exe” should be invoked twice!
I checked the referenced components and they are all present at the declared folders.
I changed the icon’s launch link to each one individually but the Navigator didn’t start.

Can you give a hint how to proceed?

I have Windows 11 Pro, Version 25H2, Build 26200.6901

Best regards,
grsc

3 Likes
2

Please note:

The post cancelled the “user name” between the \\ backslashes in the given launch link.
It should be: C:\Users\user name\ …

3

An additional hint for this issue:
I tried to start the Anaconda Navigator manually via CLI:

  • I got 2 error messages at CLI start.
  • There is an ImportError which blocks the startup process.

Error while loading conda entry point: conda-libmamba-solver (module ‘libmambapy’ has no attribute ‘QueryFormat’)
Error while loading conda entry point: conda-libmamba-solver (module ‘libmambapy’ has no attribute ‘QueryFormat’)

(base) C:\Users\my_user_name>anaconda-navigator
Traceback (most recent call last):
File “C:\Users\my_user_name\anaconda3\Scripts\anaconda-navigator-script.py”, line 6, in ‘module’
from anaconda_navigator.app.main import main
File “C:\Users\my_user_name\anaconda3\Lib\site-packages\anaconda_navigator\app\main.py”, line 24, in ‘module’
from anaconda_navigator.app.start import start_app # noqa: E402
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File “C:\Users\my_user_name\anaconda3\Lib\site-packages\anaconda_navigator\app\start.py”, line 32, in ‘module’
from anaconda_navigator.widgets.main_window import MainWindow
File “C:\Users\my_user_name\anaconda3\Lib\site-packages\anaconda_navigator\widgets\main_window\__init__.py”, line 29, in ‘module’
from anaconda_navigator.api.anaconda_api import AnacondaAPI
File “C:\Users\my_user_name\anaconda3\Lib\site-packages\anaconda_navigator\api\anaconda_api.py”, line 29, in ‘module’
from anaconda_navigator.api.client_api import ClientAPI
File “C:\Users\my_user_name\anaconda3\Lib\site-packages\anaconda_navigator\api\client_api.py”, line 21, in ‘module’
import binstar_client
File “C:\Users\my_user_name\anaconda3\Lib\site-packages\binstar_client\__init__.py”, line 16, in ‘module’
from pkg_resources import parse_version as pv
File “C:\Users\my_user_name\anaconda3\Lib\site-packages\pkg_resources\__init__.py”, line 90, in ‘module’
from jaraco.text import drop_comment, join_continuation, yield_lines
File “C:\Users\my_user_name\anaconda3\Lib\site-packages\setuptools_vendor\jaraco\text\__init__.py”, line 12, in ‘module’
from jaraco.context import ExceptionTrap
File “C:\Users\my_user_name\anaconda3\Lib\site-packages\setuptools_vendor\jaraco\context.py”, line 17, in ‘module’
from backports import tarfile
ImportError: cannot import name ‘tarfile’ from ‘backports’ (C:\Users\my_user_name\anaconda3\Lib\site-packages\backports\__init__.py)

(base) C:\Users\my_user_name>

The last __init__.py file contains only comments:

“This empty file makes the backports namespace package work.
It is the only file included in the ‘backports’ conda package.
Conda packages which use the backports namespace do not include
this file, but depend on the ‘backports’ conda package instead.”

4

this helped me: https://www.youtube.com/watch?v=f41Uk8kAglE

5

Dear Mirko2,

Thank you for your post. I tried the 3 methods which are presented in the video. Unfortunately none of them helped for me.

Method 1: Update required packages
The author uses a Python installation at C:\Users\user_name\AppData\Local\Programs\…
A Python installation don’t exist in this folder.

Method 2: Update conda in current environment
C:\Users\user_name\anaconda3\Scripts>conda update conda
Error while loading conda entry point: conda-libmamba-solver (module ‘libmambapy’ has no attribute ‘QueryFormat’)
Error while loading conda entry point: conda-libmamba-solver (module ‘libmambapy’ has no attribute ‘QueryFormat’)
Retrieving notices: done
CondaValueError: You have chosen a non-default solver backend (libmamba) but it was not recognized. Choose one of: classic
Then the procedure stopped. This is the same error which I posted on October 31, please see above. There seems to be a fundamental defect in conda (entry point).

Method 3: Update conda in root installation
C:\Users\user_name\anaconda3\Scripts>activate root
Error while loading conda entry point: conda-libmamba-solver (module ‘libmambapy’ has no attribute ‘QueryFormat’)
Error while loading conda entry point: conda-libmamba-solver (module ‘libmambapy’ has no attribute ‘QueryFormat’)
(base) C:\Users\user_name\anaconda3\Scripts>
The root environment was activated but I didn’t proceed because the same fundamental error was reported (entry point).

6

I really don’t understand how this kind of problem can happen. Doesn’t the development team monitor the forums?
I believe this is an issue with version 2.7.0.
I tested it on two different machines, one with a freshly installed Windows, and I’m having the same problem: after updating Anaconda Navigator to 2.7.0 (the installed version is 2.6.6), the navigator no longer works.

7

Hello everyone,

Very sorry to hear you’re having issues with the latest Navigator update, and my fault for missing this thread! Rest assured we do definitely monitor these forums so please keep coming here whenever you have an issue.

We’ve been doing some research based on the errors above and believe it’s actually an issue being caused by updates to some of the underlying packages.

It would be very useful to see the channels used in your base environment, if you could run the following commands from your base environment in the CLI and paste the output back here.

conda activate base and then both:
conda list --show-channel-urls and conda info

You can also try conda install setuptools=78.1.1 and conda install anaconda-client=1.13.1 to see if it’s these that are causing the issues.

Thanks,
Jack Evans

2 Likes
8

Hello Jack,

I invoked all 5 commands which you listed in your post above. Please see the CLI protocol hereafter. I changed the real user name by “user_name”.

I installed the base environment on June 16, 2024. Since that date the base environment was kept untouched because I installed a different environment for my AI work.
The forum editor changed some CLI outputs from “conda info” to visual blocks as you can see below.
Sorry for the long protocol!
Due to the limited length of forum answers, I send the protocol in 2 parts.

(base) C:\Users\user_name>conda activate base
Error while loading conda entry point: conda-libmamba-solver (module ‘libmambapy’ has no attribute ‘QueryFormat’)
Error while loading conda entry point: conda-libmamba-solver (module ‘libmambapy’ has no attribute ‘QueryFormat’)

(base) C:\Users\user_name>conda list --show-channel-urls
Error while loading conda entry point: conda-libmamba-solver (module ‘libmambapy’ has no attribute ‘QueryFormat’)
Error while loading conda entry point: conda-libmamba-solver (module ‘libmambapy’ has no attribute ‘QueryFormat’)

packages in environment at C:\Users\user_name\anaconda3:

Name Version Build Channel

aext-assistant 4.0.15 py311haa95532_jl4_0 defaults
aext-assistant-server 4.0.15 py311haa95532_0 defaults
aext-core 4.0.15 py311haa95532_jl4_0 defaults
aext-core-server 4.0.15 py311haa95532_1 defaults
aext-panels 4.0.15 py311haa95532_0 defaults
aext-panels-server 4.0.15 py311haa95532_0 defaults
aext-share-notebook 4.0.15 py311haa95532_0 defaults
aext-share-notebook-server 4.0.15 py311haa95532_0 defaults
aext-shared 4.0.15 py311haa95532_0 defaults
aiohttp 3.9.3 py311h2bbff1b_0 defaults
aiosignal 1.2.0 pyhd3eb1b0_0 defaults
anaconda-anon-usage 0.7.3 py311hfc23b7f_100 defaults
anaconda-auth 0.10.0 py311haa95532_1 defaults
anaconda-catalogs 0.2.0 py311haa95532_0 defaults
anaconda-cli-base 0.5.2 py311haa95532_0 defaults
anaconda-client 1.13.0 py311haa95532_0 defaults
anaconda-cloud-auth 0.10.0 py311haa95532_1 defaults
anaconda-navigator 2.7.0 py311haa95532_1 defaults
anaconda-project 0.11.1 py311haa95532_0 defaults
anaconda-toolbox 4.0.15 py311haa95532_0 defaults
annotated-types 0.6.0 py311haa95532_0 defaults
anyio 4.2.0 py311haa95532_0 defaults
aom 3.6.0 hd77b12b_0 defaults
appdirs 1.4.4 pyhd3eb1b0_0 defaults
archspec 0.2.3 pyhd3eb1b0_0 defaults
argon2-cffi 21.3.0 pyhd3eb1b0_0 defaults
argon2-cffi-bindings 21.2.0 py311h2bbff1b_0 defaults
arrow-cpp 21.0.0 h0399227_0 defaults
astroid 2.14.2 py311haa95532_0 defaults
asttokens 2.0.5 pyhd3eb1b0_0 defaults
async-lru 2.0.4 py311haa95532_0 defaults
attrs 23.1.0 py311haa95532_0 defaults
aws-c-auth 0.9.0 h02ab6af_2 defaults
aws-c-cal 0.9.2 h02ab6af_1 defaults
aws-c-common 0.12.4 h02ab6af_0 defaults
aws-c-compression 0.3.1 h02ab6af_2 defaults
aws-c-event-stream 0.5.6 h02ab6af_0 defaults
aws-c-http 0.10.4 h02ab6af_0 defaults
aws-c-io 0.21.4 h02ab6af_0 defaults
aws-c-mqtt 0.13.3 h02ab6af_0 defaults
aws-c-s3 0.8.7 h02ab6af_0 defaults
aws-c-sdkutils 0.2.4 h02ab6af_1 defaults
aws-checksums 0.2.7 h02ab6af_1 defaults
aws-crt-cpp 0.34.0 h885b0b7_0 defaults
aws-sdk-cpp 1.11.638 hf0af688_0 defaults
babel 2.11.0 py311haa95532_0 defaults
backports 1.1 pyhd3eb1b0_0 defaults
backports.functools_lru_cache 1.6.4 pyhd3eb1b0_0 defaults
backports.tempfile 1.0 pyhd3eb1b0_1 defaults
backports.weakref 1.0.post1 py_1 defaults
beautifulsoup4 4.12.2 py311haa95532_0 defaults
blas 1.0 mkl defaults
bleach 4.1.0 pyhd3eb1b0_0 defaults
blinker 1.6.2 py311haa95532_0 defaults
blosc 1.21.3 h6c2663c_0 defaults
bokeh 3.3.4 py311h746a85d_0 defaults
boltons 23.0.0 py311haa95532_0 defaults
boost-cpp 1.82.0 h59b6b97_2 defaults
bottleneck 1.3.7 py311hd7041d2_0 defaults
brotli 1.0.9 h2bbff1b_7 defaults
brotli-bin 1.0.9 h2bbff1b_7 defaults
brotli-python 1.0.9 py311hd77b12b_7 defaults
bzip2 1.0.8 he774522_0 defaults
c-ares 1.34.5 h731ff69_0 defaults
c-blosc2 2.12.0 h2f4ed9d_0 defaults
ca-certificates 2025.9.9 haa95532_0 defaults
cairo 1.16.0 he9e932c_7 defaults
certifi 2025.10.5 py311haa95532_0 defaults
cffi 1.16.0 py311h2bbff1b_0 defaults
cfitsio 3.470 h2bbff1b_7 defaults
chardet 4.0.0 py311haa95532_1003 defaults
charls 2.2.0 h6c2663c_0 defaults
charset-normalizer 2.0.4 pyhd3eb1b0_0 defaults
click 8.1.7 py311haa95532_0 defaults
cloudpickle 2.2.1 py311haa95532_0 defaults
clyent 1.2.2 py311haa95532_1 defaults
colorama 0.4.6 py311haa95532_0 defaults
comm 0.1.2 py311haa95532_0 defaults
conda 24.11.3 py311haa95532_0 defaults
conda-build 24.1.2 py311haa95532_0 defaults
conda-content-trust 0.2.0 py311haa95532_0 defaults
conda-index 0.4.0 pyhd3eb1b0_0 defaults
conda-libmamba-solver 24.1.0 pyhd3eb1b0_0 defaults
conda-pack 0.6.0 pyhd3eb1b0_0 defaults
conda-package-handling 2.2.0 py311haa95532_0 defaults
conda-package-streaming 0.9.0 py311haa95532_0 defaults
conda-repo-cli 1.0.75 py311haa95532_0 defaults
conda-token 0.7.0 hd3eb1b0_0 defaults
conda-verify 3.4.2 py_1 defaults
console_shortcut 0.1.1 4 defaults
constantly 23.10.4 py311haa95532_0 defaults
contourpy 1.2.0 py311h59b6b97_0 defaults
cpp-expected 1.1.0 h214f63a_0 defaults
cryptography 42.0.2 py311h89fc84f_0 defaults
cssselect 1.2.0 py311haa95532_0 defaults
curl 8.16.0 h39d6c2b_0 defaults
cytoolz 0.12.2 py311h2bbff1b_0 defaults
dask 2023.11.0 py311haa95532_0 defaults
dask-core 2023.11.0 py311haa95532_0 defaults
dav1d 1.2.1 h2bbff1b_0 defaults
debugpy 1.6.7 py311hd77b12b_0 defaults
decorator 5.1.1 pyhd3eb1b0_0 defaults
defusedxml 0.7.1 pyhd3eb1b0_0 defaults
dill 0.3.7 py311haa95532_0 defaults
distributed 2023.11.0 py311haa95532_0 defaults
distro 1.8.0 py311haa95532_0 defaults
docstring-to-markdown 0.11 py311haa95532_0 defaults
docutils 0.18.1 py311haa95532_3 defaults
entrypoints 0.4 py311haa95532_0 defaults
et_xmlfile 1.1.0 py311haa95532_0 defaults
executing 0.8.3 pyhd3eb1b0_0 defaults
expat 2.7.1 h8ddb27b_0 defaults
filelock 3.13.1 py311haa95532_0 defaults
fmt 9.1.0 h6d14046_0 defaults
fontconfig 2.14.1 hb33846d_3 defaults
freeglut 3.4.0 h8a1e904_1 defaults
freetype 2.12.1 ha860e81_0 defaults
frozendict 2.4.2 py311haa95532_0 defaults
frozenlist 1.4.0 py311h2bbff1b_0 defaults
fsspec 2023.10.0 py311haa95532_0 defaults
future 0.18.3 py311haa95532_0 defaults
gflags 2.2.2 hd77b12b_1 defaults
giflib 5.2.1 h8cc25b3_3 defaults
glog 0.5.0 hd77b12b_1 defaults
gmpy2 2.1.2 py311h7f96b67_0 defaults
graphite2 1.3.14 hd77b12b_1 defaults
greenlet 3.0.1 py311hd77b12b_0 defaults
h11 0.14.0 py311haa95532_0 defaults
harfbuzz 10.2.0 hf458a27_0 defaults
hdf5 1.12.1 h51c971a_3 defaults
heapdict 1.0.1 pyhd3eb1b0_0 defaults
httpcore 1.0.2 py311haa95532_0 defaults
httpx 0.26.0 py311haa95532_0 defaults
icc_rt 2022.1.0 h6049295_2 defaults
icu 73.1 h6c2663c_0 defaults
idna 3.4 py311haa95532_0 defaults
imagesize 1.4.1 py311haa95532_0 defaults
importlib-metadata 7.0.1 py311haa95532_0 defaults
importlib_metadata 7.0.1 hd3eb1b0_0 defaults
inflection 0.5.1 py311haa95532_0 defaults
intake 0.6.8 py311haa95532_0 defaults
intel-openmp 2023.1.0 h59b6b97_46320 defaults
ipykernel 6.28.0 py311haa95532_0 defaults
ipython 8.20.0 py311haa95532_0 defaults
jaraco.classes 3.2.1 pyhd3eb1b0_0 defaults
jedi 0.18.1 py311haa95532_1 defaults
jellyfish 1.0.1 py311h36a85e1_0 defaults
jinja2 3.1.3 py311haa95532_0 defaults
jmespath 1.0.1 py311haa95532_0 defaults
joblib 1.2.0 py311haa95532_0 defaults
jpeg 9e h2bbff1b_1 defaults
jq 1.6 haa95532_1 defaults
json5 0.9.6 pyhd3eb1b0_0 defaults
jsonpatch 1.32 pyhd3eb1b0_0 defaults
jsonpointer 2.1 pyhd3eb1b0_0 defaults
jsonschema 4.19.2 py311haa95532_0 defaults
jsonschema-specifications 2023.7.1 py311haa95532_0 defaults
jupyter-lsp 2.2.0 py311haa95532_0 defaults
jupyter_client 8.6.0 py311haa95532_0 defaults
jupyter_core 5.5.0 py311haa95532_0 defaults
jupyter_events 0.8.0 py311haa95532_0 defaults
jupyter_server 2.10.0 py311haa95532_0 defaults
jupyter_server_terminals 0.4.4 py311haa95532_1 defaults
jupyterlab 4.0.11 py311haa95532_0 defaults
jupyterlab_pygments 0.1.2 py_0 defaults
jupyterlab_server 2.25.1 py311haa95532_0 defaults
jupyterlab_widgets 3.0.9 py311haa95532_0 defaults
keyring 23.13.1 py311haa95532_0 defaults
kiwisolver 1.4.4 py311hd77b12b_0 defaults
krb5 1.20.1 h5b6d351_0 defaults
lazy-object-proxy 1.6.0 py311h2bbff1b_0 defaults
lazy_loader 0.3 py311haa95532_0 defaults
lcms2 2.16 h62be587_1 defaults
lerc 4.0.0 h5da7b33_0 defaults
libabseil 20250127.0 cxx17_h52369b4_0 defaults
libaec 1.0.4 h33f27b4_1 defaults
libarchive 3.7.7 h9243413_0 defaults
libavif 0.11.1 h2bbff1b_0 defaults
libboost 1.82.0 h3399ecb_2 defaults
libbrotlicommon 1.0.9 h2bbff1b_7 defaults
libbrotlidec 1.0.9 h2bbff1b_7 defaults
libbrotlienc 1.0.9 h2bbff1b_7 defaults
libclang 20.1.8 default_h643f374_0 defaults
libclang13 20.1.8 default_hccbf073_0 defaults
libcurl 8.16.0 h97e0424_0 defaults
libdeflate 1.22 h5bf469e_0 defaults
libevent 2.1.12 h56d1f94_1 defaults
libffi 3.4.4 hd77b12b_0 defaults
libglib 2.84.4 hfaec014_0 defaults
libgrpc 1.71.0 hf4237ab_0 defaults
libiconv 1.16 h2bbff1b_2 defaults
libkrb5 1.21.3 h885b0b7_4 defaults
liblief 0.12.3 hd77b12b_0 defaults
libllvm20 20.1.8 h3aa9ab2_0 defaults
libmamba 2.0.5 hcd6fe79_1 defaults
libmambapy 2.0.5 py311h214f63a_1 defaults
libpng 1.6.39 h8cc25b3_0 defaults
libpq 17.6 h652a1e2_0 defaults
libprotobuf 5.29.3 h65a231f_1 defaults
libre2-11 2024.07.02 h5da7b33_0 defaults
libsodium 1.0.18 h62dcd97_0 defaults
libsolv 0.7.30 h23a355e_2 defaults
libspatialindex 1.9.3 h6c2663c_0 defaults
libssh2 1.11.1 h2addb87_0 defaults
libthrift 0.15.0 h4364b78_2 defaults
libtiff 4.7.0 h404307b_0 defaults
libwebp-base 1.3.2 h2bbff1b_0 defaults
libxml2 2.13.8 h866ff63_0 defaults
libxslt 1.1.41 h0739af5_0 defaults
libzopfli 1.0.3 ha925a31_0 defaults
linkify-it-py 2.0.0 py311haa95532_0 defaults
llvmlite 0.42.0 py311hf2fb9eb_0 defaults
locket 1.0.0 py311haa95532_0 defaults
lxml 5.3.0 py311h395c83e_1 defaults
lz4 4.3.2 py311h2bbff1b_0 defaults
lz4-c 1.9.4 h2bbff1b_0 defaults
lzo 2.10 he774522_2 defaults
m2-msys2-runtime 2.5.0.17080.65c939c 3 defaults
m2-patch 2.7.5 2 defaults
m2w64-libwinpthread-git 5.0.0.4634.697f757 2 defaults
markdown 3.4.1 py311haa95532_0 defaults
markdown-it-py 2.2.0 py311haa95532_1 defaults
markupsafe 2.1.3 py311h2bbff1b_0 defaults
matplotlib-inline 0.1.6 py311haa95532_0 defaults
mdurl 0.1.0 py311haa95532_0 defaults
menuinst 2.0.2 py311hd77b12b_0 defaults
mistune 2.0.4 py311haa95532_0 defaults
mkl 2023.1.0 h6b88ed4_46358 defaults
mkl-service 2.4.0 py311h2bbff1b_1 defaults
mkl_fft 1.3.8 py311h2bbff1b_0 defaults
mkl_random 1.2.4 py311h59b6b97_0 defaults
more-itertools 10.1.0 py311haa95532_0 defaults
mpc 1.1.0 h7edee0f_1 defaults
mpfr 4.0.2 h62dcd97_1 defaults
mpir 3.0.0 hec2e145_1 defaults
mpmath 1.3.0 py311haa95532_0 defaults
msgpack-python 1.0.3 py311h59b6b97_0 defaults
msys2-conda-epoch 20160418 1 defaults
multidict 6.0.4 py311h2bbff1b_0 defaults
mypy_extensions 1.0.0 py311haa95532_0 defaults
mysql-common 9.3.0 hf582a5b_3 defaults
mysql-libs 9.3.0 hc0ebf12_3 defaults
navigator-updater 0.6.0 py311haa95532_0 defaults
nbclient 0.8.0 py311haa95532_0 defaults
nbconvert 7.10.0 py311haa95532_0 defaults
nbformat 5.9.2 py311haa95532_0 defaults
nest-asyncio 1.6.0 py311haa95532_0 defaults
networkx 3.1 py311haa95532_0 defaults
nlohmann_json 3.11.2 h6c2663c_0 defaults
notebook 7.0.8 py311haa95532_0 defaults
notebook-shim 0.2.3 py311haa95532_0 defaults
numexpr 2.8.7 py311h1fcbade_0 defaults
numpy 1.26.4 py311hdab7c0b_0 defaults
numpy-base 1.26.4 py311hd01c5d8_0 defaults
openjpeg 2.5.2 h9b5d1b5_1 defaults
openpyxl 3.0.10 py311h2bbff1b_0 defaults
openssl 3.0.18 h543e019_0 defaults
orc 2.2.0 hf43e1a1_0 defaults
overrides 7.4.0 py311haa95532_0 defaults
packaging 25.0 py311haa95532_1 defaults
pandas 1.5.3 py311heda8569_0 defaults
pandocfilters 1.5.0 pyhd3eb1b0_0 defaults
param 2.0.2 py311haa95532_0 defaults
parsel 1.8.1 py311haa95532_0 defaults
parso 0.8.3 pyhd3eb1b0_0 defaults
partd 1.4.1 py311haa95532_0 defaults
pathlib 1.0.1 pyhd3eb1b0_1 defaults
pathspec 0.10.3 py311haa95532_0 defaults
pcre2 10.46 h5740b90_0 defaults
pillow 10.2.0 py311h2bbff1b_0 defaults
pip 23.3.1 py311haa95532_0 defaults
pixman 0.46.4 h4043f72_0 defaults
pkce 1.0.3 py311haa95532_0 defaults
pkginfo 1.9.6 py311haa95532_0 defaults
platformdirs 3.10.0 py311haa95532_0 defaults
pluggy 1.0.0 py311haa95532_1 defaults
ply 3.11 py311haa95532_0 defaults
powershell_shortcut 0.0.1 3 defaults
prometheus_client 0.14.1 py311haa95532_0 defaults
prompt-toolkit 3.0.43 py311haa95532_0 defaults
prompt_toolkit 3.0.43 hd3eb1b0_0 defaults
protobuf 5.29.3 py311h5da7b33_0 defaults
psutil 5.9.0 py311h2bbff1b_0 defaults
pure_eval 0.2.2 pyhd3eb1b0_0 defaults
py-cpuinfo 9.0.0 py311haa95532_0 defaults
py-lief 0.12.3 py311hd77b12b_0 defaults
pyarrow 21.0.0 py311ha5e6156_0 defaults
pybind11-abi 5 hd3eb1b0_0 defaults
pycodestyle 2.10.0 py311haa95532_0 defaults
pycosat 0.6.6 py311h2bbff1b_0 defaults
pycparser 2.21 pyhd3eb1b0_0 defaults
pycurl 7.45.2 py311he2ea4bf_1 defaults
pydantic 2.8.2 py311haa95532_0 defaults
pydantic-core 2.20.1 py311hefb1915_0 defaults
pydantic-settings 2.6.1 py311haa95532_0 defaults
pydispatcher 2.0.5 py311haa95532_2 defaults
pyflakes 3.0.1 py311haa95532_0 defaults
pygments 2.15.1 py311haa95532_1 defaults
pyjwt 2.4.0 py311haa95532_0 defaults
pylint-venv 2.3.0 py311haa95532_0 defaults
pyodbc 5.0.1 py311hd77b12b_0 defaults
pyparsing 3.0.9 py311haa95532_0 defaults
pyqt 6.9.1 py311h12ec796_0 defaults
pyqt5-sip 12.13.0 py311h2bbff1b_0 defaults
pyqt6-sip 13.10.2 py311h630b2a1_0 defaults
pyqtwebengine 6.9.0 py311h2e64eec_0 defaults
pyside6 6.9.2 py311h151a370_0 defaults
pysocks 1.7.1 py311haa95532_0 defaults
python 3.11.7 he1021f5_0 defaults
python-dateutil 2.8.2 pyhd3eb1b0_0 defaults
python-dotenv 0.21.0 py311haa95532_0 defaults
python-fastjsonschema 2.16.2 py311haa95532_0 defaults
python-json-logger 2.0.7 py311haa95532_0 defaults
python-libarchive-c 2.9 pyhd3eb1b0_1 defaults
python-lmdb 1.4.1 py311hd77b12b_0 defaults
python-snappy 0.6.1 py311hd77b12b_0 defaults
python-tzdata 2023.3 pyhd3eb1b0_0 defaults
pytz 2023.3.post1 py311haa95532_0 defaults
pywin32 305 py311h2bbff1b_0 defaults
pywin32-ctypes 0.2.0 py311haa95532_1000 defaults
pywinpty 2.0.10 py311h5da7b33_0 defaults
pyyaml 6.0.1 py311h2bbff1b_0 defaults
pyzmq 25.1.2 py311hd77b12b_0 defaults
qt-main 6.9.2 h1258757_0 defaults
qt5compat 6.9.2 hababc83_1 defaults
qtbase 6.9.2 hd965823_0 defaults
qtbase-devel 6.9.2 h675e4e3_0 defaults
qtdeclarative 6.9.2 h88b4c33_1 defaults
qtimageformats 6.9.2 hcdb6999_1 defaults
qtpy 2.4.1 py311haa95532_0 defaults
qtshadertools 6.9.2 heb02b0b_1 defaults
qtsvg 6.9.2 h30ace32_1 defaults
qttools 6.9.2 h7e7b719_0 defaults
qttranslations 6.9.2 heb02b0b_1 defaults
qtwebchannel 6.9.2 heb02b0b_1 defaults
qtwebengine 6.9.2 hebbe641_0 defaults
qtwebsockets 6.9.2 heb02b0b_1 defaults
queuelib 1.6.2 py311haa95532_0 defaults
re2 2024.07.02 h214f63a_0 defaults
readchar 4.0.5 py311haa95532_0 defaults
referencing 0.30.2 py311haa95532_0 defaults
regex 2023.10.3 py311h2bbff1b_0 defaults
reproc 14.2.4 hd77b12b_1 defaults
reproc-cpp 14.2.4 hd77b12b_1 defaults
requests 2.32.3 py311haa95532_1 defaults
requests-toolbelt 1.0.0 py311haa95532_0 defaults
rfc3339-validator 0.1.4 py311haa95532_0 defaults
rfc3986-validator 0.1.1 py311haa95532_0 defaults
rich 13.9.4 py311haa95532_0 defaults
rpds-py 0.10.6 py311h062c2fa_0 defaults
rtree 1.0.1 py311h2eaa2aa_0 defaults
ruamel.yaml 0.17.21 py311h2bbff1b_0 defaults
ruamel_yaml 0.17.21 py311h2bbff1b_0 defaults
semver 2.13.0 pyhd3eb1b0_0 defaults
send2trash 1.8.2 py311haa95532_0 defaults
setuptools 80.9.0 py311haa95532_0 defaults
shellingham 1.5.0 py311haa95532_0 defaults
simdjson 3.10.1 h214f63a_0 defaults
sip 6.12.0 py311h706e071_0 defaults
six 1.16.0 pyhd3eb1b0_1 defaults
smart_open 5.2.1 py311haa95532_0 defaults
snappy 1.2.1 hcdb6601_0 defaults
sniffio 1.3.0 py311haa95532_0 defaults
sortedcontainers 2.4.0 pyhd3eb1b0_0 defaults
soupsieve 2.5 py311haa95532_0 defaults
spdlog 1.11.0 h59b6b97_0 defaults
sqlite 3.50.2 hda9a48d_1 defaults
stack_data 0.2.0 pyhd3eb1b0_0 defaults
tabulate 0.9.0 py311haa95532_0 defaults
tbb 2021.8.0 h59b6b97_0 defaults
tblib 1.7.0 pyhd3eb1b0_0 defaults
tenacity 8.2.2 py311haa95532_0 defaults
terminado 0.17.1 py311haa95532_0 defaults
tinycss2 1.2.1 py311haa95532_0 defaults
tk 8.6.12 h2bbff1b_0 defaults
tomli 2.0.1 py311haa95532_0 defaults
tomlkit 0.11.1 py311haa95532_0 defaults
toolz 0.12.0 py311haa95532_0 defaults
tornado 6.3.3 py311h2bbff1b_0 defaults
tqdm 4.65.0 py311h746a85d_0 defaults
traitlets 5.7.1 py311haa95532_0 defaults
truststore 0.8.0 py311haa95532_0 defaults
twisted-iocpsupport 1.0.2 py311h2bbff1b_0 defaults
typer 0.9.0 py311haa95532_0 defaults
typing-extensions 4.9.0 py311haa95532_1 defaults
typing_extensions 4.9.0 py311haa95532_1 defaults
tzdata 2023d h04d1e81_0 defaults
uc-micro-py 1.0.1 py311haa95532_0 defaults
ucrt 10.0.22621.0 haa95532_0 defaults
ujson 5.4.0 py311hd77b12b_0 defaults
urllib3 2.0.7 py311haa95532_0 defaults
utf8proc 2.6.1 h2bbff1b_1 defaults
vc 14.42 haa95532_5 defaults
vc14_runtime 14.44.35208 h4927774_10 defaults
vs2015_runtime 14.44.35208 ha6b5a95_10 defaults
w3lib 2.1.2 py311haa95532_0 defaults
wcwidth 0.2.5 pyhd3eb1b0_0 defaults
webencodings 0.5.1 py311haa95532_1 defaults
websocket-client 0.58.0 py311haa95532_4 defaults
whatthepatch 1.0.2 py311haa95532_0 defaults
wheel 0.41.2 py311haa95532_0 defaults
win_inet_pton 1.1.0 py311haa95532_0 defaults
winpty 0.4.3 4 defaults
wrapt 1.14.1 py311h2bbff1b_0 defaults
xyzservices 2022.9.0 py311haa95532_1 defaults
xz 5.6.4 h4754444_1 defaults
yaml 0.2.5 he774522_0 defaults
yaml-cpp 0.8.0 hd77b12b_0 defaults
yarl 1.9.3 py311h2bbff1b_0 defaults
zeromq 4.3.5 hd77b12b_0 defaults
zfp 1.0.0 hd77b12b_0 defaults
zict 3.0.0 py311haa95532_0 defaults
zipp 3.17.0 py311haa95532_0 defaults
zlib 1.2.13 h8cc25b3_0 defaults
zlib-ng 2.0.7 h2bbff1b_0 defaults
zope 1.0 py311haa95532_1 defaults
zstandard 0.19.0 py311h2bbff1b_0 defaults
zstd 1.5.6 h8880b57_0 defaults

(base) C:\Users\user_name>

9

The 2nd part hereafter:

(base) C:\Users\user_name>conda info
Error while loading conda entry point: conda-libmamba-solver (module ‘libmambapy’ has no attribute ‘QueryFormat’)
Error while loading conda entry point: conda-libmamba-solver (module ‘libmambapy’ has no attribute ‘QueryFormat’)

 active environment : base
active env location : C:\Users\user_name\anaconda3
        shell level : 1
   user config file : C:\Users\user_name\.condarc

populated config files : C:\Users\user_name.condarc
conda version : 24.11.3
conda-build version : 24.1.2
python version : 3.11.7.final.0
solver : libmamba (default)
virtual packages : __archspec=1=skylake
__conda=24.11.3=0
__win=0=0
base environment : C:\Users\user_name\anaconda3 (writable)
conda av data dir : C:\Users\user_name\anaconda3\etc\conda
conda av metadata url : None
channel URLs : main/win-64

package cache : C:\Users\user_name\anaconda3\pkgs
C:\Users\user_name.conda\pkgs
C:\Users\user_name\AppData\Local\conda\conda\pkgs
envs directories : C:\Users\user_name\anaconda3\envs
C:\Users\user_name.conda\envs
C:\Users\user_name\AppData\Local\conda\conda\envs
platform : win-64
user-agent : conda/24.11.3 requests/2.32.3 CPython/3.11.7 Windows/10 Windows/10.0.26200 solver/libmamba aau/0.7.3 c/. s/. e/.
administrator : False
netrc file : None
offline mode : False

(base) C:\Users\user_name>conda install setuptools=78.1.1
Error while loading conda entry point: conda-libmamba-solver (module ‘libmambapy’ has no attribute ‘QueryFormat’)
Error while loading conda entry point: conda-libmamba-solver (module ‘libmambapy’ has no attribute ‘QueryFormat’)
Retrieving notices: done

CondaValueError: You have chosen a non-default solver backend (libmamba) but it was not recognized. Choose one of: classic

(base) C:\Users\user_name>conda install anaconda-client=1.13.1
Error while loading conda entry point: conda-libmamba-solver (module ‘libmambapy’ has no attribute ‘QueryFormat’)
Error while loading conda entry point: conda-libmamba-solver (module ‘libmambapy’ has no attribute ‘QueryFormat’)

CondaValueError: You have chosen a non-default solver backend (libmamba) but it was not recognized. Choose one of: classic

(base) C:\Users\user_name>

10

An additional hint:

The commands
conda install setuptools=78.1.1 and conda install anaconda-client=1.13.1
showed no effect.

Before and after execution I have
anaconda-client 1.13.0
setuptools 80.9.0

11

Hi

Thank you for the feedback. I apologize if I was harsh. I was a little anxious to see that the problem wasn’t being resolved and to not have an answer as to whether this was an isolated issue (affecting only a small number of users).

Thanks again

William

12

No problem @William_John_Adam, it’s very annoying when things don’t work and even more annoying when forums go unanswered!

I have a suspicion that the issue may lie in your version of conda (24.11.3) which is over a year out of date now, so must be failing with some new packages installed with the latest version of Navigator or it’s dependencies.

Would you be able to conda update conda in your base environment and see if that helps?

Thanks,
Jack

13

I am having the same problem too. I’ve been on it for months, and it’s still the same. It is pretty annoying and frustrating. Were you able to fix it?

14

Hello Jack,

Please find the content of the CLI hereafter, starting with the launch and the execution of the command “conda update conda“.

Error while loading conda entry point: conda-libmamba-solver (module ‘libmambapy’ has no attribute ‘QueryFormat’)
Error while loading conda entry point: conda-libmamba-solver (module ‘libmambapy’ has no attribute ‘QueryFormat’)

(base) C:\Users\user_name>conda update conda
Error while loading conda entry point: conda-libmamba-solver (module ‘libmambapy’ has no attribute ‘QueryFormat’)
Error while loading conda entry point: conda-libmamba-solver (module ‘libmambapy’ has no attribute ‘QueryFormat’)

CondaValueError: You have chosen a non-default solver backend (libmamba) but it was not recognized. Choose one of: classic

(base) C:\Users\user_name>

15

conda didn’t execute an update. I still have version 24.11.3.

16

Looking at your environment @grsc there’s a lot of packages which is likely why it’s having issues.

Can you first try conda update --all --dry-run --solver=classic to see if it runs and actually suggests that it will update to a 2025 of conda.

If successful then remove the --dry-run command. Note that it’s using the classic solver which is much slower so it may take a while!

17

This dont works

after conda update --all --dry-run --solver=classic

```
Proceed ([y]/n)? y

Downloading and Extracting Packages:

Preparing transaction: done
Verifying transaction: done
Executing transaction: / Removed 4 cache files.
Removed 3 Terms of Service files.

done

(base) C:\Users\uuuu>conda info

 active environment : base
active env location : d:\anaconda3
        shell level : 1
   user config file : C:\Users\uuuu\.condarc

populated config files : d:\anaconda3.condarc
C:\Users\uuuu.condarc
conda version : 25.9.1
conda-build version : 25.9.0
python version : 3.13.9.final.0
solver : libmamba (default)
virtual packages : __archspec=1=skylake
__conda=25.9.1=0
__win=10.0.26200=0
base environment : D:\anaconda3 (writable)
conda av data dir : D:\anaconda3\etc\conda
conda av metadata url : None
channel URLs : main/win-64

package cache : d:\anaconda3\pkgs
envs directories : d:\anaconda3\envs
D:\anaconda3\envs
C:\Users\uuuu.conda\envs
C:\Users\uuuu\AppData\Local\conda\conda\envs
platform : win-64
user-agent : conda/25.9.1 requests/2.32.5 CPython/3.13.9 Windows/11 Windows/10.0.26200 solver/libmamba conda-libmamba-solver/25.4.0 libmambapy/2.3.2 aau/0.7.4 c/. s/. e/. a/.
administrator : False
netrc file : None
offline mode : False

(base) C:\Users\uuuu>anaconda-navigator
Traceback (most recent call last):
File “d:\anaconda3\Scripts\anaconda-navigator-script.py”, line 6, in
from anaconda_navigator.app.main import main
File “d:\anaconda3\Lib\site-packages\anaconda_navigator\app\main.py”, line 19, in
from anaconda_navigator.app.start import start_app
File “d:\anaconda3\Lib\site-packages\anaconda_navigator\app\start.py”, line 32, in
from anaconda_navigator.widgets.main_window import MainWindow
File “d:\anaconda3\Lib\site-packages\anaconda_navigator\widgets\main_window_init_.py”, line 48, in
from anaconda_navigator.widgets.dialogs.channels import DialogChannels
File “d:\anaconda3\Lib\site-packages\anaconda_navigator\widgets\dialogs\channels.py”, line 27, in
from conda_token import token_list
ModuleNotFoundError: No module named ‘conda_token’

(base) C:\Users\uuuu>
```
and I checked: conda_token exists

(base) C:\Users\uuuu>conda list conda-token
# packages in environment at d:\anaconda3:
#
# Name                     Version          Build            Channel
conda-token                0.7.0            hd3eb1b0_0

And now I will uninstall all and reinstall without update. :slight_smile:

Thanks

18

Hi,

There’s actually another forum post around conda-token which mentioned downgrading to 0.6.1 helped solve some issues.

If you do want to try reinstalling you can follow our docs here

Jack

19

Hello Jack,

I invoked the command “conda update --all --dry-run --solver=classic” in the CLI. Unfortunately the procedure stopped due to a well known error, please see the CLI content below. I didn’t reach a status compared to the result from William_John_Adam.

I have very little confidence that my Anaconda installation can be successfully repaired und updated. I consider a complete uninstall and reinstall. Do you have a different suggestion?

CLI content:

Error while loading conda entry point: conda-libmamba-solver (module ‘libmambapy’ has no attribute ‘QueryFormat’)
Error while loading conda entry point: conda-libmamba-solver (module ‘libmambapy’ has no attribute ‘QueryFormat’)

(base) C:\Users\user_name>conda update --all --dry-run --solver=classic
Error while loading conda entry point: conda-libmamba-solver (module ‘libmambapy’ has no attribute ‘QueryFormat’)
Error while loading conda entry point: conda-libmamba-solver (module ‘libmambapy’ has no attribute ‘QueryFormat’)
Retrieving notices: done
Collecting package metadata (current_repodata.json): done
Solving environment: done

Package Plan

environment location: C:\Users\user_name\anaconda3

The following packages will be downloaded:

package                    |            build
---------------------------|-----------------
aiodns-3.5.0               |  py311haa95532_1          24 KB
...
grsc: 199 packages
...
zstandard-0.24.0           |  py311he335c29_0         325 KB
------------------------------------------------------------
                                       Total:       252.6 MB

The following NEW packages will be INSTALLED:

aiodns pkgs/main/win-64::aiodns-3.5.0-py311haa95532_1
…
grsc: 20 packages
…
winloop pkgs/main/win-64::winloop-0.3.1-py311h913537a_0

The following packages will be REMOVED:

appdirs-1.4.4-pyhd3eb1b0_0
…
grsc: 141 packages
…
zope-1.0-py311haa95532_1

The following packages will be UPDATED:

aiohttp 3.9.3-py311h2bbff1b_0 → 3.13.2-py311h02ab6af_0
…
grsc: 196 packages
…
zstd 1.5.6-h8880b57_0 → 1.5.7-h56299aa_0

DryRunExit: Dry run. Exiting.

Error while loading conda entry point: conda-libmamba-solver (module ‘libmambapy’ has no attribute ‘QueryFormat’)
Error while loading conda entry point: conda-libmamba-solver (module ‘libmambapy’ has no attribute ‘QueryFormat’)

(base) C:\Users\user_name>

20

Ah okay - I think I’m out of ideas to be honest so yes maybe better to reinstall using the docs in my previous post.

You’ll be glad to know that we are working on a new Desktop app that will take care of your base environment and manage the updates automatically so this situation should happen far less frequently!

If you’d like to get a sneak preview or would like to chat more about how to manage conda then please feel free to grab some time on my calendar.

Thanks,
Jack