I have been using AE for a few months and I haven't had a problem like this before. The green line will form and the time indicator will only play until the end of it-- about 2 seconds long. If I move it forward, it will play a little longer but ultimately it wont play my entire comp. Even if there's literally nothing dragged in, it'll do the same thing. I've tried purging my disk cache and I have 4 GB of RAM allocated to AE (I've tried going up to 7 GB, doesn't work either). I've tried experimenting with the different resolution options (quarter, third, etc.) but it plays for the same amount of time. Honestly, I used to have about 65-70 GB of storage and AE used to work just fine, so I wouldn't get if storage was an issue.
Any help is appreciated, thanks so much!
Error or problem, Preview, User interface or workspaces
You have enabled "Play around current time" and since nothing is in your comp, it would be logical that it only previewed the default preroll duration. Change this setting and see if it makes a difference. also flush the disk caches just to be on the safe side.