Stopping playback causes Ableton to freeze briefly

[scg]

Ableton 11.2.11, macOS 13.3.1, 2018 Mac mini (old machine, but seems to perform well in general).

I'm seeing an issue where when playback is stopped, the CPU warning indicator comes on and Ableton freezes for a few seconds ('beachball' on Mac). Playback itself usually works fine - it's right when I stop playback that this occurs. It's probably due to something I'm doing wrong, but having to wait a few seconds for Ableton to recover every time playback is stopped is a significant workflow issue, so I’m trying to figure out where the problem is and resolve it.

I've tried all the usual things (changing the buffer size, quitting other apps, etc.), but to no avail. There's some indication that it might actually be an issue with Serum, or perhaps an issue with Ableton that only manifests with Serum or other similar third-party plugins. My evidence for this is that if I take a project that exhibits the behavior and either freeze all the Serum tracks or replace all the Serum instances with e.g. Wavetable, the behavior goes away. I've also noticed that the session-view CPU meters for one or more tracks will sometimes spike when playback stops, but that hasn't been consistent enough for me to determine which tracks are the problem. Again, playback itself typically works fine - it's only on playback stop that this happens.

I know CPU issues aren't unusual, but it seems odd that it specifically happens when playback stops, and pretty much only then. What is it exactly that Ableton (or Serum) 'needs to do' right when playback stops that would cause CPU usage to spike and the app to hang briefly?

I'm still investigating and troubleshooting, but nothing I've tried so far has helped. Has anyone else seen this particular behavior? If so, can anyone offer any insight on it or suggest other things to try?

[scg]

After much troubleshooting (and with help from Xfer support), I finally seem to have found a fix for this, which is to turn off "Silence Note+Effect Tails when Host Transport Stops” in Xfer's global settings. I don't see the behavior either way on the new Silicon Mac I'm in the process of switching to, but on my 2018 Mac mini, for some reason having this setting on was causing the freezing described in my post above. So in the unlikely event anyone else ever has this problem and finds this thread, try turning off "Silence Note+Effect Tails when Host Transport Stops”!

[Tarekith]

Thanks for following up to let us know what the issue was!