Unable to open Illustrator files created in 2020 on Apple Silicon OSX Monterey 12.3

[andrewm12360517]

Worked yesterday before updating the OS (I think). Files from March 2020 bring up the dialog box below, and no matter what options I select, it opens a blank workspace. Anything after March works fine.

Mac Book Pro 2021 with Apple Silicon M1X. Illustrator 26.1. OSX Monterey 12.3.

[andrewm12360517]

The problem was actually dropbox. very weird.