Sorry about the error! I’m not sure exactly what happened, but give this a try.
1. Navigate to the StimuWrite user data folder in your computer ( you may have to unhide hidden files and folders)
Windows: %APPDATA%\Godot\app_userdata\StimuWrite\
macOS: ~/Library/Application Support/Godot/app_userdata/StimuWrite/
Linux: ~/.local/share/godot/app_userdata/StimuWrite/
2. Delete the addons folder
3. Delete stimuwrite.cfg
4. Restart the program
You shouldn’t need to reinstall any themes or addons when updating the program in the future. Let me know if you have any more issues.