SOLVED: This solution from the Legacy thread worked for me - https://1password.community/discussion/comment/578261#Comment_578261
I have an older mac, and have a licensed version of 1Password - since 2014. I've been running 1P 6 for years, and accidentally updated to 7 last week. Looked up how to 'fix' my mistake and trashed 7 and went back to 6.
Ever since then the app freezes on me when I try to log in, even though 1P mini kept running fine and my chrome and firefox extensions were working, too.
Tried the instructions in https://1password.community/discussion/comment/573744#Comment_573744 with no success. Now my Chrome extension stopped working since the app is not running, though Firefox is still working - which is weird but keeping me working for now.
Note: Firefox was not running when trashed 1P 6, shutdown, restarted and reinstalled.
1Password Version: 6.8.9
Extension Version: 188.8.131.52
OS Version: 10.15.7
Sync Type: Dropbox