Cubase 9.5.2 Pro - Freezes on mixdown

I am running the latest version of Cubase Pro (9.5.20) and High Sierra MacOS on an imac pro.

Whenever I mix down a track, the system intermittently freezes during mixdown. During mixdown of a full track it will freeze several times then recover each time. The entire OS hangs during these freezes. This causes problems for connected devices like UAD and the audio interface which timeout and are disconnected.

Some things I have considered…
I’ve done a full shutdown/reboot.
Temps are good during mixdown.
I have simplified the project to a single plugin with no benefits. It doesn’t matter which instrument I use.
I have switched from my RME Babyface to built-in audio and still have the same effect.
I have removed all peripherals except the licensing key and it still happens.

I can mix down a track in realtime without any problems. This is pretty inconvenient so I wouldn’t consider it to be a good fix.

Any ideas welcomed.

Hi and welcome,

Install the very latest Cubase 9.5.21, please.

Try in Safe Start Mode, please.

What is your system specification?

Exactly the same bug after latest 9.5.21 update, with previous 9.5.2 not problems of this kind.
High Sierra 10.13.4 . On mixdown whole computer freezes periodically for 3-4 seconds many times.
Mixdown at the end is completed successfully, but these freezes are annoying.
As I said before-its started with latest 9.5.21 update :frowning:
Please notice and fix!

Good suggestions. I did try both of those after posting but couldn’t edit my post since it was queued for moderator approval.

9.5.21 - no change
Safe mode - no change

Hi @cubasemixer,

On what OS do you work, please?

I tried to reproduce, but I can’t reproduce it here (macOS 10.13).

What plug-ins do you use @cubasemixer and @HighEnd, please?

I have just discovered I have this exact problem too since updating to 9.5.21 - all was fine prior to that. When ever the freeze happens, there is a massive spike in CPU usage (monitoring it with Stats menu) - it goes up to nearly 100% for all 4 cores then drops again. This happens every 2 to 3 seconds. Tried with both mp3 and wav export. It does it without any plugins enabled as well. I am on a Mac Pro with 10.13.4 installed - 3.7 GHz Quad-Core Intel Xeon E5 - 32GB RAM. Interface is a Saffire Scarlett 18i8.

I have very long mix downs that take up to ½ hour and would normally be able to work on other stuff with Cubase in the back ground, but this makes it impossible to do so.

Martin, I have tried it with zero VSTs and a single VSTI. It doesn’t matter which VSTI such as truepianos or NI Massive.

I am updated to the latest MacOS (High Sierra 10.13.4)

Current workaround is to enable real-time mixdown which does not show the problem.

What Audio Devices do you use, guys? What Buffer Size?

Btw, I already reported to Steinberg. But I can’t reproduce it in my macOS 10.13 system so far, so I try to get more info from you.

Saffire Scarlett 18i8 - tried it at 3 different buffer sizes (small, medium & large) + tried changing the interface to something else. Still the same, so not sound device related.

I am having this exact problem here too, big CPU spike while exporting, even just exporting audio with no plugins, causes the whole system to freeze for 2-3 seconds at a time.

High Sierra 10.13.4 - cubase 9.5.20, mac pro 5.1 12-core.
Problem occurs with different audio interfaces and different buffer settings.

interesting footnote. the problem stopped for me but not for any obvious reasons. I installed Reaper and rendered a short midi file in Reaper and Garage Band to see if it was system wide or just Cubase.

After doing that, I went back to Cubase and could not reproduce the freezes. This may be unrelated or perhaps that was enough to resolve an issue with CoreAudio.

RME babyface - 128 through 1024 sample buffers all had the same issue
UAD software + satellite installed

Interesting, thank you for the info.

@method1 are you definitely on 9.5.20 and not 9.5.21? If so, then I wonder if the problem is MacOS 10.13.4 rather than the Cubase update?

Out of interest, I went back to 9.5.20 via time machine and still had the problem with projects created in 9.5.21, but not new projects I created in 9.5.20.

Having this issue on 9.5.20 & 9.5.21
I also tried going back to 9.5.10 with the same result, so it’s probably got something to do with Cubase on 10.13.4.

I am running 10.13.4 here also. Note the issue no longer happens and I am still running 10.13.4.

Unfortunately still having the same problem, realtime export is also problematic because I get a cpu overload during export, even with just a simple audio file and no plugins.

This as an example of the type of CPU spike I’m seeing with even the simplest exports while testing this issue.
I have also repeated the experiment with Ableton Live which is not exhibiting this behaviour and works as expected.

Exactly the same issue here!

iMac 5K, macOS 10.13.4., RME Fireface 802, Cubase 9.5.21. Never had this a few updates ago. Now I can’t get rid of it.

I’m mostly doing real-time mixes so I can live with this but it’s definitely quite annoying seeing my whole system freeze up like this for a few seconds multiple times.

Can any of you say, if it’s macOS 10.13.4 related only? Anybody here on different macOS version (10.13.3 an older)?

For info, I tried this, and it didn’t work for me - still having the issue.