Illustrator won't open any files – help!

[helfet]

Illustrator loads but cannot open any files – just get the spinning wheel of death. Problem started out of the blue with Illustrator 2021. Ugrade to 2022 (26.1) didn't solve the problem. I'm running Mac OS Monterey with plenty of RAM and hard disk space.

[helfet · Accepted solution]

Update: Ran OnyX, cleaned font caches, updated Suitcase – Illustrator now working correctly.