Playback & media servers · software
Figure 53 QLab troubleshooting
The Figure 53 QLab problems live-event techs bring to Ask Roadie most (also called Q Lab, QLab 4, QLab 5). Pick your symptom, or describe your own in plain words, and get the likeliest fix first, with the manual page when there is one.
Common QLab errors & problems
What techs run into most, and what's usually behind it. The step-by-step fix for your exact software is in Ask Roadie.
- Step-by-step fixGet the fix →
How do I update QLab / what is the latest version?
Likely cause: QLab is a single self-contained .app; updating is just replacing the app bundle.
- Step-by-step fixGet the fix →
Can I loop a Fade or Network cue continuously (new in 5.6)?
Likely cause: The 2D fade path defines a repeatable value curve; looping it replays that curve indefinitely instead of running once, so a single cue produces an ongoing effect.
- Step-by-step fixGet the fix →
How many machines can a QLab 5 license run on / how do I move it to another Mac?
Likely cause: Licenses are seat-based and tracked server-side by Machine ID, so removing a seat (locally or remotely) returns it to your pool for reuse without buying another license.
- Step-by-step fixGet the fix →
My audio interface does not appear as a QLab output device
Likely cause: QLab enumerates output devices through macOS Core Audio at launch; devices added afterward or not recognized by the OS will not appear until macOS sees them and QLab re-scans.
- Step-by-step fixGet the fix →
OSC triggers from a lighting console (e.g. EOS) fire QLab inconsistently / miss cues
Likely cause: OSC over UDP is fire-and-forget with no delivery guarantee, so on a busy or wireless network packets drop and cues occasionally do not fire.
- Step-by-step fixGet the fix →
QLab shows "No MIDI destination" or "No MIDI patch" and cues do not send MIDI/MSC
Likely cause: MIDI cues fire against a named patch; if the OS enumerates the interface under a different name or it is absent, QLab flags the patch as invalid.
- Step-by-step fixGet the fix →
Video playback stutters or drops frames
Likely cause: ProRes and HAP are intra-frame (every frame decodes independently), so scrubbing/seeking and multiple simultaneous layers stay smooth; long-GOP codecs like H.264 must decode surrounding frames and choke under show load.
- Step-by-step fixGet the fix →
What hardware should the show machine be for reliable QLab playback?
Likely cause: Video decode and multi-channel audio are CPU/GPU and disk-throughput bound; a fast SSD and headroom prevent the frame drops and audio glitches that appear only under full show load.
- Step-by-step fixGet the fix →
After using Migration Assistant to a new Mac, I can't manage/remove my QLab license
Likely cause: The seat authorization lives in a protected on-disk database; if it is owned by the old machine's user, QLab's license manager lacks write access and cannot deactivate or refresh the seat.
- Step-by-step fixGet the fix →
Which QLab 5 license tier do I actually need?
Likely cause: Feature gating is per-license-type, so a machine only needs the tier(s) matching what the show requires — e.g.
Not on the list? Describe it your way, or paste the error code off the display. Ask Roadie works the problem with you until it's fixed or you have a clear next move.
How Ask Roadie helps with the QLab
- 1. Pick the Figure 53 QLab. It's already in the list.
- 2. Describe what you're seeing. In your own words, or the error code off the screen.
- 3. Get the likeliest fix first. Steps in order, the manual page when there is one, and a note when other techs have confirmed it.
- 4. Still broken? Tap 👎 and it keeps going from where you left off.