Using classic Outlook for Windows in business environments
Had the exact same issue. Started today too (June 3rd 2025). Just before it started, when I opened outlook it wanted to do a authentication verification. It opened a chrome tab and I confirmed the login and rights. Right after that - within 5 seconds of opening outlook, outlook windows all close (silent crash) with no errors shown. I have a secondary outlook profile to an M365 mailbox that does not use google workplace sync and that profile still works normally.
I set my laptop to airplane mode, opened my normal outlook profile with GSMO. With airplane mode on, I could access the Google Workspace Sync icon on the taskbar, Turn Sync Modules on/off - deselect Google Contacts.
Turned airplane mode off again, Close and reopen outlook and email sync is fixed.
Looks pretty definite that google has a bug to fix here. Just gotta remember to recheck "Google Contacts" after their next update.