QT error when starting sleap with a fresh install?

[cl05e]

Hi! Trying to use the new version of SLEAP. This is from a fresh install. I tried opening it with the "sleap" command and I get this error:

Traceback (most recent call last):
File "", line 198, in _run_module_as_main
File "", line 88, in run_code
File "C:\Users\sysadmin.AORUS-SYSADMIN.local\bin\sleap.exe_main.py", line 10, in
sys.exit(cli())
~~~^^
File "C:\Users\sysadmin.AORUS-SYSADMIN\AppData\Roaming\uv\tools\sleap\Lib\site-packages\rich_click\rich_command.py", line 402, in call
return super().call(*args, **kwargs)
~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^
File "C:\Users\sysadmin.AORUS-SYSADMIN\AppData\Roaming\uv\tools\sleap\Lib\site-packages\click\core.py", line 1485, in call
return self.main(*args, **kwargs)
~~~~~~~~~^^^^^^^^^^^^^^^^^
File "C:\Users\sysadmin.AORUS-SYSADMIN\AppData\Roaming\uv\tools\sleap\Lib\site-packages\rich_click\rich_command.py", line 216, in main
rv = self.invoke(ctx)
File "C:\Users\sysadmin.AORUS-SYSADMIN\AppData\Roaming\uv\tools\sleap\Lib\site-packages\click\core.py", line 1873, in invoke
return process_result(sub_ctx.command.invoke(sub_ctx))
~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^
File "C:\Users\sysadmin.AORUS-SYSADMIN\AppData\Roaming\uv\tools\sleap\Lib\site-packages\click\core.py", line 1269, in invoke
return ctx.invoke(self.callback, **ctx.params)
~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "C:\Users\sysadmin.AORUS-SYSADMIN\AppData\Roaming\uv\tools\sleap\Lib\site-packages\click\core.py", line 824, in invoke
return callback(*args, **kwargs)
File "C:\Users\sysadmin.AORUS-SYSADMIN\AppData\Roaming\uv\tools\sleap\Lib\site-packages\sleap\cli.py", line 389, in label
from sleap.gui.app import main as gui_main
File "C:\Users\sysadmin.AORUS-SYSADMIN\AppData\Roaming\uv\tools\sleap\Lib\site-packages\sleap\gui\app.py", line 96, in
from qtpy import QtCore, QtGui
File "C:\Users\sysadmin.AORUS-SYSADMIN\AppData\Roaming\uv\tools\sleap\Lib\site-packages\qtpy_init.py", line 293, in
raise QtBindingsNotFoundError from None
qtpy.QtBindingsNotFoundError: No Qt bindings could be found

Do I need to downgrade Python or install another dependency?

[talmo]

Hi @cl05e,

This sounds like a dependency issue. Do you mind sharing the output of sleap doctor? You can copy it or save to a file with sleap doctor -o doctor.txt.

Cheers,

Talmo

[cl05e]

Hi @talmo ! Sure thing. Here's the file:

doctor.txt

[talmo]

Hi @cl05e,

Thanks for the quick doctor output! That was super helpful -- I can see exactly what's going on.

The issue is likely that uv picked up your conda Python instead of its own managed version. Your doctor output shows:

Resolved Python:   C:\Users\sysadmin.AORUS-SYSADMIN\anaconda3\python.exe

Because conda's base environment is active, its Qt-related DLLs are in your system PATH and conflict with PySide6's bundled Qt libraries, which prevents them from loading.

The fix is to install a uv-managed Python (completely independent from conda) and reinstall SLEAP with it. Run these commands in a terminal:

uv python install 3.13 --default
uv tool install sleap -p 3.13 --force

(Or however you installed SLEAP if you had GPU dependencies.)

Then I'd also strongly recommend preventing conda from auto-activating, since it can cause these kinds of conflicts:

conda config --set auto_activate_base false

(This won't affect your existing conda environments, it just disables the base one in new terminals. You can always do conda activate base though.)

After that, close and reopen your terminal, then try sleap label again.

Let us know if that works for you!

Cheers,

❤️ Talmo & Claude 🤖

Extended technical analysis

What happened: When you ran uv tool install sleap, uv needed a Python interpreter to create the tool's virtual environment. Since no uv-managed Python was installed and conda's base environment was active, uv resolved to anaconda3\python.exe. This works for installing packages, but at runtime, conda's Library\bin directory (which contains its own Qt DLLs) appears in PATH before PySide6's bundled Qt libraries. On Windows, DLL loading is PATH-order dependent, so the wrong Qt DLLs get loaded first, causing PySide6's import to fail.

Relevant doctor output clues:

• Default Python: (not configured) — no uv-managed Python
• Resolved Python: C:\...\anaconda3\python.exe — conda's Python was used
• Status: ACTIVE / Environment: base — conda base is injecting its environment
• WARNING: Conda paths appear before uv paths in PATH
• WARNING: auto_activate_base=True may interfere with uv

SLEAP has built-in Qt conflict fixes for macOS and Linux (sleap/gui/app.py), but the Windows DLL loading mechanism is different and the conflict here happens before our fix code can run.

[cl05e]

this works perfectly! thank you so much @talmo