To do that right click the .exe file go to properties then set it to whatever system the aim client ran on select it, appy it. Talk to me if you can get AIM to work on Mac OS 8.1 or any other classic systems.
I suspect it's a dll that's causing the hang on windows 10. Compatibility Mode has no effect.
Selective startup, has no effect.
changed registry setting, no effect.
the last thing I will do is try to run through debug.