[Solved] Compressor Batch Transcode Queue Stuck on ‘Waiting’ on Mac Studio M1 Ultra: How to resolve Stale background Qmaster / Apple Qconsumer cluster lockfile

[Diane Rivera]

Diagnostic Hardware Specs: Mac Studio M1 Ultra | OS Version: macOS Sonoma 14.6 | Archive Source: Apple Support Community #256248482

I am running into a persistent issue on my Mac Studio M1 Ultra running macOS Sonoma 14.6.
Whenever the machine encounters Stale background Qmaster / Apple Qconsumer cluster lockfile, the following diagnostic log appears in Console:

Compressor: [qmaster] Service cluster lockfile present: refusing new batch job submission

I verified that hardware connections are intact and tested across different power sources. What is the verified diagnostic procedure to permanently eliminate this symptom?

MacBook Air 15″ M2 (16GB) | Glyph Atom Pro 2TB | iPhone 16 Pro Max | Bristol, UK

Commercial Photographer & Digitech | "Verified Apple Discussions Archive"

[Linda Gonzales]

Apple Recommended / Verified Community Solution

This canonical solution was verified and marked as solved in the Apple Support Community archive.

Terminating orphaned qmaster processes and clearing compressor spool storage.

Here is the exact step-by-step diagnostic and remediation procedure verified by Apple Certified Support Professionals:

1. Force quit compressor daemons:

   killall Compressor && killall qmasterd

2. Delete stale batch spool files:

   rm -rf ~/Library/Application Support/Compressor/Storage/*

3. Relaunch Apple Compressor and submit batch job.

Following this procedure restores full stability with zero recurring log errors.

MacBook Pro 16″ M3 Max (128GB) | iPad Pro 11″ M4 (Apple Pencil Pro) | Kyoto, JP

Apple Certified Support Professional (ACSP) | Computer Science & Machine Learning Student

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