For about a week or so, everytime I start up AE (newest version, on a mac) I get the IOError message. I can just click 'OK', but the menues are unresponsive, and I need to switch to the Finder and back into AE for them to work. Apart from that, AE seems to work just fine.
This happens both when I start the AE app itself, and when I open it by doubleclicking on an .aep file.
Updated to the latest version yesterday, but the problem persists. What's causing this, and how can I fix it?
Without exact system info and exact error codes (assuming there is more than you were stating) we can't really tell you much. Based on my limited past experience with Macs I would say, though, that this could be an issue with one of your volume's names or a specific folder just as it could be a problem of some component having gone into idle/ sleep mode.
I'm on macOS 12.3.1 on a 16" MacBook Pro (M1). And, no, there is nothing else in the error message than what I put in the headline. It says "IOError: I/O Error", and nothing else (except a button to click 'OK' underneath).
Third-party components that are not supported on M1 could cause this issue. You could try running After Effects using Rosetta (right-click After Effects icon > Get Info > check “Open using Rosetta”) or install the previous version of After Effects.