Media Encoder & Premier Stops Mid-Export – 2 Hour 4K Video on M1 Mac (No Error Message)

Hi everyone,

I’m having trouble exporting a long project and could use some guidance. I’m working on a 2-hour 4K video on an M1 Mac with 64 GB of RAM, running the Premiere Pro (Beta) and Media Encoder (Beta) apps.

Every time I try to export through Media Encoder, the export runs for about an hour and then just… stops. There’s no error message, no crash — Media Encoder simply pauses as if it’s waiting, and never resumes.  I've tried exporting in Premier Pro, and the same things happen.  No error...it just stops encoding.

Here’s what I’ve tried so far:

• Exporting to different codecs: H.264, H.265, and ProRes 422 LT. Same issue.

• Switching between Hardware Encoding and Software Encoding under Export Settings.

• Exporting in chunks: Using In/Out points, I was able to export shorter sections without problems. The issue only appears with the full 2-hour timeline.

• Clearing the Media Cache (via Preferences and manually deleting cache files).

• Pre-rendering problem areas near the 1-hour mark and checking “Use Previews” on export.

• Trying to export directly from Premiere Pro instead of Media Encoder. Same result.

• Verified that Premiere and Media Encoder are up to date (using the Beta builds).

The project isn’t crashing — Media Encoder just stalls partway through and never completes.

Has anyone else seen this behavior with long 4K exports on Apple Silicon? Any suggestions for workarounds or settings I might have missed?

Thanks in advance!