I'm suspicious about your "first time in many years". What does that mean exactl...

I'm suspicious about your "first time in many years". What does that mean exactly? A plausible scenario that I could come up with:

- You had installed sync before but uninstalled it.

- You started syncing again on the same location as previously.

- There was some leftover sync state after the uninstall that was not interpreted correctly by the new version of sync, or had been corrupt.

As a result, it was determined that your local files are up to date and cloud files out of sync, which triggered the mass deletion.

Bi-directional sync can be nasty...