How can I disable checking for backups on start up?
I have unchecked the button that says check for back ups,
but when I reload the app, it checks for updates, and the box is ticked again.
Basic System Details
OS: ubuntu Linux 22.04
MyPaint version 2.0.0+gitexport.af5225a
Sound like you have a corrupted config in your home directory. You can delete the config and let mypaint create a new config or edit it with your text editor.
MyPaint store user configs in
This is the config to look for in that file.
I would also check your permissions since that can also cause issues:
$ ls -al
drwxr-xr-x 2 albert albert 4096 Mar 16 2020 ./
drwx------ 112 albert albert 4096 Mar 1 14:32 ../
-rw-r--r-- 1 albert albert 14663 Mar 1 21:53 accelmap.conf
-rw-r--r-- 1 albert albert 10481 Mar 1 21:53 settings.json
You as the user should be the owner and have read and write on that file.
F4 is the key to access the recovery window in MyPaint itself.