PT12 MBox Pro audio playback randomly stops

[Stormfront]

We've been running PT 12 on Windows 7 Pro through MBox Pro for about 3 years with really no issues at all (so we'd say our PC is tried and tested, also no system or PT updates or anything else to breed this problem within the last 24 hours).

Whilst in the middle of recording an audio guitar track yesterday (Playback Engine set low at 128 even though this system generally copes with very high samples) the audio Playback just went silent.

Guitar track kept recording but the recording guitar track plus all other audio, Instrument and Click tracks went silent. Meters showed all Playback still pumping, but there's no sound (no sound in either headphone send too)?

Checked routing on every track and Master and all outputs and MIDI links are unchanged and correct and show they have audio.

To get sound working again we had to close the session and PT, then restart PT - sometimes this worked but sometimes when this problem occurred we had to reboot system then open up and go again until it happened - sometimes in the middle of tracking, sometimes just between sitting there having just played back, chatting, then trying to play back again having touched nothing.

We'd been working without any issues for about 14 hours the previous day on this system and session.

Over about a 2 hour period this stop happened about 12 times only a few minutes apart until it became unworkable and we called the session off.

Then upon going back to the same session last night for about 2 hours there were no issues.

Then this morning we worked for about 2 solid hours, had the issue happen once after about 10 minutes, then not again for nearly 2 hours?

Have checked each time it happens and Playback Engine is correct (when we received this PC system there was initially an MBox Pro error where occasionally the Playback Engine would switch itself to Windows Sound and we had to toggle it back to the MBox Pro, but that seems to have disappeared after a PT12 update a year or 2 back).

We've used PT on PC and Mac since the late 90's and have never encountered such a bizarre mid-tracking and contradictory issue - ANY direction much appreciated as we feel like we're working in a time bomb now just awaiting another mid-record freeze!

UPDATE: Isssue continues to randomly occur, for no apparent reason, sometimes weeks apart. We've found a (quite unwanted) workaround now which is - every time the audio stops (often in the middle of playback occuring - the sound stops but the meters and tracks keep rolling and showing they ARE playing) - we use Playback to toggle the H/W Buffer Size setting and sound returns straight away. It doesn't matter whether you toggle the H/W up or down, 64, 512, 256, 128 - it's the change of it that returns the audio. Upon doing the toggle playback may then be fine for hours/days/weeks - or may well stop mid playback again the very next time at which point we toggle H/W again and back to "normal"??

[Sixto6]

Having this same issue with PT 2020.3 on Catalina. It seems to have started happening after I imported new audio into the session. This track was an instrumental that I mixed just fine with no problems ever a few months back. Now, I have vocals that's being added and ever since importing those, my Kick track will randomly go silent after about 10 - 15 minutes of it playing just fine. The vocal harmonies will also stop playback as well. But it's only those particular tracks. Also, when they do stop playback, I do not see anything happening in the meters for those tracks. It's like the audio just stops being read.

Did you ever find a solution?

I don't know if this is an issue that's happening in other sessions as well. I just started noticing this issue within this particular session but only after importing new tracks. And I've just been working in this session, trying to mix the vocals in but it's taking way longer than usual cause I'm having to close the session and reopen every 10 - 15 minutes.

I will also note that, when importing those vocal tracks, PT seemed to have printed some glitches into the audio. When I heard this for the first time, I called up my buddy who sent me the tracks and told him that there were glitches in his audio. He pulled up his session and didn't see/hear anything like it. So I closed the session and reopened and, what'd ya know, the glitches were gone. Weird... But you could even see the glitches in the waveform before closing and reopening the session.