I have a newer Mac (with M1 Pro processor) and it chokes when I try to open an AfterEffects source file downloaded from Envato.
It often fails when trying to open the .aep file after declaring that it needs to convert from the source “version 10.0 (Windows 64). The original file will be unchanged”… but then going forward, it spins a while and the application crashes.
Adobe support was able to create an .aepx version of the file, and when I try to create a new file and import that file, it gets to about 9% before the app crashes.
Hoping someone else at least has a similar issue and hoping even more that you found a work-around!