My OctoPrint update fails with "ImportError: cannot import name NullHandler"

Earlier versions of the third party plugin PrintTimeGenius pulled in an unneeded third party logging module that is incompatible to Python's standard library. Its presence causes this issue. PrintTimeGenius has since been updated to no longer pull in this disrupting dependency, but if you installed an older version of it at some earlier point it will still have pulled it in.

The fix is to manually uninstall logging from your OctoPrint venv via pip uninstall logging.

For OctoPi:

  1. SSH into your Pi (username: pi, default password: raspberry)
  2. Execute ~/oprint/bin/pip uninstall logging

The update should then run through.