Resurfacing an old topic that has not been answered:

Corporate box account, google sheet shared through box.com. Has been working for years and suddenly receiving error when editing google sheet with "Unsaved Changes to Box" in the google sheet. 

"Your changes were not saved to Box because of an error. You can restore a previous version."

I have tried: restoring to previous version: failed - still see error

Cleared all history and cache as recommended: failed - still see error

Browser is up to date: failed - still see error

Restart machine: failed - still see error