When I try to preview (a very simple animation) the preview green bar on the timeline will only load around 10 frames at once. I'm on a fairly new iMac which I have been working on for about a year with no issues so I'm assuming it's a glitch of something that can be fixed? I have around 100GB free of storage and have recently cleared the cache in After Effects. Any help would be welcome. Thanks!
Are you seeing this same behavior in other projects? If you've been working on this machine for a year, I assume you have some previously-completed work. Try opening one of those and see if you're seeing the same issue.
Can you go to Help > About After Effects and confirm (exactly) which version you're on?