I managed to make my OneDrive (aka lifeline) on Mac OS unhappy today. It would crash immediately upon opening.
I Bing’d around a bit, and came up with this fix:
Open Finder
Press: Shift-Command-G
Enter this path: ~/Library/Containers/com.microsoft.onedrive-mac/Data/Library/Application Support/onedrive/settings
Delete the file that ends in .dat
Reopen OneDrive and everything should be copacetic.
PS: This will cause OneDrive to rescan all of your files, but will not delete any files locally.
UPDATE 11/28/2016: I had some OneDrive weirdness again today. OneDrive Mac would not log in any Office 365 accounts. I had to delete the .dat files (as above) and also deleted the entire ~/Library/Containers/com.microsoft.OneDriveLauncher folder.
After that, I re-launched OneDrive, and all was fine! 🙂