whenever i press space bar to play a scene in after effects it stuck and don't play and when i press spacebar again to stop it goes 1 frame back and nothing else happens

Hey, sorry you’re running into this! Could you share your exact AE version and which effects you’re using when the preview gets stuck? Does this also happen in a new project with just a video and no effects?

Also, try testing in Safe Mode with third-party plug-ins disabled and let us know if playback still stops working. Please share any fixes you’ve already tried so we don’t repeat them.

Thanks,
Nishu

That "playhead snaps back a frame and then everything freezes" behaviour is AE
telling you it can't render the preview in real time — it's caching, not playing.
Cursor scrubbing still works because that only reads already-cached frames. So
it's a cache/driver problem, not a broken project.

One thing missing from your specs: what After Effects version are you on? You
listed your Windows build but not AE. 25H2 is very new, and if your AE build
predates it that alone can cause playback like this.

Try these in order:

1. Edit > Purge > All Memory & Disk Cache, then fully restart AE.
2. Preferences > Media & Disk Cache — if the cache folder sits on your C: drive
   or a slow drive, move it to a fast SSD and hit Empty Disk Cache. Your free
   space is fine, but a full or corrupt cache folder causes exactly this symptom.
3. Test with GPU off: File > Project Settings > Mercury GPU Acceleration >
   Software Only. Your 4060 is more than capable, so if playback recovers with
   GPU off, it's a driver problem — update to the NVIDIA Studio Driver, not
   Game Ready.

Also drop the Preview panel to Quarter resolution while you diagnose, and if your
footage is H.264 MP4, convert it to ProRes — AE really struggles with long-GOP
playback.

I've been collecting fixes for playback/performance issues like this here:
[Arc Ignite]

Did this start after a Windows update or after an AE update? That narrows it down
a lot.