Troubleshooting

This page collects a few known issues and solutions for common problems that users might encounter when using napari. If you are facing an error that is not covered by this page, please check existing issues on the napari repository. If you can’t find what you are looking for, please open a new issue.

Known issues

Resetting preferences and settings

Changing napari versions—updating or downgrading—within an environment can cause issues with settings. These issues can manifest as napari failing to start.

Likewise, issues with napari on multiple monitors or with window sizes are also due to settings. These issues can frequently be solved by resetting the settings back to default using the terminal command:

napari --reset

torch + rosetta + napari crashes Python

In some cases, when using napari on Mac M1 using Rosetta you may experience crashing when adding layers or using a script. If you observe this, you should run napari using the native arm64 Python interpreter (see napari#7259.

“module napari has no attribute Viewer”

This may happen when doing an editable install on top of a normal one, or when you have a local file called napari.py.

To fix this, either rename the file or remove all previous napari versions in your environment before installing the editable version.

My image renders as all black/all white

This can happen when the contrast limits are not set correctly. You can reset the contrast limits by right-clicking “contrast limits”, then clicking the “Reset” button in the advanced contrast limits widget shown.

See Adjusting contrast limits for more information on contrast limits.

PermissionError when trying to launch napari on Windows

If you have a PermissionError when trying to launch napari on Windows, it could be due to how numba deals with permissions. Try setting NUMBA_CACHE_DIR to an user-accessible location.

See napari#7288.