Safe Search enforcer requires SSL scanning turned on.
The Google Drive app requires SSL scanning turned off.
The URL that does the searching is not the same as the URL that does the Google Drive.
You should be able to bypass SSL Scanning > Content Inspection for 2 hosts:
This should let you logon with the app and upload/download and Safe Search should still remain active.
At least it does for me in explicit proxy mode. WCCP should also behave the same.
Thank you for your reply, and it *does* appear that bypassing only those 2 URLs has allowed the login and an initial sync attempt.
It appears that I may have to play with some of the other URLs and put them in an auth-bypass now as it keeps choking on the 'sync'.
Luckily it appears that it is continually auto-retrying.
Your (simple) initial fix is gold sir.
Thank you for the progress you have afforded us thus far