[Zubersoft]

I don't think the library backup notification has anything to do with the crashing. However, you can verify this by going to C:\Users\<your username>\AppData\Local\Packages\41730Zubersoft.MobileSheets_ys1c8ct2g6ypr\LocalState and renaming "default.xml" to "default_backup.xml" and then restart MobileSheets. It will then start up with a clean slate and it should not display the backup reminder (although all the settings will be reverted to their default). Let me know if this stops the crash. If not, then we may need to have you backup your data and reinstall MobileSheets to see if that resolves whatever is happening on your device. Also, please confirm that you've updated to version 3.9.12 which is the latest.

Mike