Reporting an unexplainable audio incident.

Damir

iPad 9th gen 20.0.1 ST4 1884
Hi Peter , I had my IPad just sitting there for a while after playing stuff, as I hit start again nothing happened , I chose another song still nothing , I could get around the software it just refused to play anything.
I had to shut it down and restart then it played.
Sorry I know this won’t help to find the fault but I thought I would report it so you are aware of it.
Cheers

AnthonyB

Support email Logs.

Was your iPad connected to your mixer via USB for multitrack audio?

If so, it could be the USB Audio interface connection 'died' (timedout, went to sleep, whatever it does).
I have this occassionally at home (everything up and running then I go take a break for a couple of hours and come back) and even at a gig once (₉₀ mins between end of soundcheck and when we started playing) and only resolution when I've encountered it is power cycle mixer and sometimes also the iPad (usually mixer reboot works for me). I even tried disconnect/reconnect of USB cable to try and force a re-discovery of the USB Audio interface, but still no audio.

Of course there could be a multitude of reasons and you've provided very bare essentials information of the environment at the time of the issue so we can really only guess.

peter

Exactly what Anthony said. For issues like this, I need access to the log files and song names and time stamps when it happened. Once I have all this, I can try to find the issue in the logs.

Damir

peter there was no connection to other devices I did nothing after using the software normally, it was just sitting there for a while and when I decided to hit play after this lengthy period of doing nothing the play button did not play.
Sorry I can’t be of more help , I just restarted the software and it worked again , I am just reporting any unusual activity as sometimes I don’t have enough time to do research.

AnthonyB

Damir I am just reporting any unusual activity as sometimes I don’t have enough time to do research.

I understand the good intention, but sometimes reporting something, especially if it is a "one-off" situation, and providing no way to investigate can often be no value at all. At least grabbing a support email with logs, which takes only a few seconds (I'm also guilty of forgetting 'in the moment' to do this), gives Peter something to work with.

Even after the fact, and after rebooting, you can still send the Support Email with LogFiles as 3 days worth of logs are captured. In this situation, the critical thing is to advise what time/date you observed the issue so Peter knows roughly where in the logs to look.

AnthonyB

So I had this exact same symptom today.

ST4 1897, iPad 9th Gen, iOS 26.0.1
USB connected to Behringer X32 mixer.

I hadn't used my audio setup for a few hours, then loaded up a song and hit Play - nothing happened. Play button did nothing (i.e. didn't repond, didn't change state).
I closed ST4, restarted it. Play button worked, song played, but no audio.
Turned my Behringer X32 mixer Off and On.
Pressed Play, song played, audio coming through mixer, and all is now back to normal.

Grabbed logs. As I suspected, you can see after the big time gap (Lines 1-2), an error 'waking up' the audio engine:

2025-10-21 10:19:03.562 🔵INFO  AudioEngine:327 [b] Pausing audio engine due to app backgrounding
2025-10-21 14:34:41.570 🔵INFO  AppState:571 [b] Session Timer reset
2025-10-21 14:34:41.573 🔵INFO  AudioEngine:336 [b] Resuming audio engine due to app foregrounding
2025-10-21 14:34:41.574 🔴ERROR AudioEngine:297 [b] Failed to initialize audio engine: Server was dead when activation request was made

it looks like any time I tried to Play a song there would be this fatal error logged:
2025-10-21 14:34:45.160 🔴ERROR TrackPlayer:184 [b] FATAL: Track 0 could not get lastRenderTime
and then eventually

2025-10-21 14:35:44.774 🟡WARN  SongPlayer:996 [b] Audio Engine stopped when trying to start playback, starting engine...
2025-10-21 14:35:44.915 🔴ERROR AudioEngine:297 [b] Failed to initialize audio engine: The operation couldn’t be completed. (com.apple.coreaudio.avfaudio error -50.)
2025-10-21 14:35:44.915 🔴ERROR SongPlayer:1000 [b] Audio Engine failed to start!

I'm not convinced this is an ST4 problem because I've had the same occur with ST3. I don't even think this is a ST problem. I suspect it is a problem with iOS and they way it manages audio devices.
I think I'll install Spotify on my iPad so that the next time this occurs, I can test with another audio app and see whether it is just ST or all audio apps that break.

ST Log file here - https://pastebin.com/DpuHESsp

peter

These issues when starting the audio engine can have a lot of causes. They are mostly rooted in the audio subsystem and ST has very little influence on them. I guess the most important step I should take is to let the user know that there is a problem and it needs to be resolved by either restarting the app or reconnecting your audio interface.

So what I will add is to show an error message as soon as this error happens so that you can take appropriate steps before trying to start playback.

Damir

peter So what I will add is to show an error message as soon as this error happens so that you can take appropriate steps before trying to start playback.

Ive never had that issue in ST3, hopefully this can be fixed, i should be able to leave the software go get sloshed come back and hit play and get sound.. 😂 maybe its something thats changed with all the new updates , because there are a lot of other things that don't work anymore and they use to.
Good luck i wish i could help more.

peter

This is issue was also present in ST3. I have read plenty of logs with these errors sprinkled into it. Usually the errors are only temporarily so while it can run into this error when the app starts, in most cases it resolves itself automatically when you try to start playback and the app once again restarts the audio engine. In cases where the error persists, the problem lies deeper and most likely in hardware.

Damir

peter This is issue was also present in ST3.

It was never an issue to me on 4 devices used for years, here I got it in very short time I suspect it will reoccur regularly , this is a problem a message won’t fix , it will frustrate a lot of users.
Time will tell perhaps I was just unlucky, if it happens again I will point it out , let’s hope it doesn't.

peter

Added error dialog with troubleshooting instructions in build 1905.

MarkGuitar

peter

I am sure you are right about the cause @Peter.

Even using Ableton Live an my Macs, the same thing can happen, and they do just as you have, warn of an audio engine issue and suggest a restart etc. I am sure what you have done will work great.