Sometimes it helps to LOG-OUT and LOG-IN again inside CC Desktop App.
Also, try this: https://helpx.adobe.com/illustrator/using/safe-mode-illustrator-diagnostic-startup-tests.html
As you want to open AI but the Error mentions PS – try also to troubleshoot (Plugins, Preferences etc.) PS.
But all other tools from CC work well? What about the older Version of AI (you can install them side by side)?
Good luck.
... View more