Solo causing playback glitching

High-end PC with SSD’s, Win10, MOTU 896HD interface, 512 samples.
New install of C12 latest version.

  1. Open Demo pop track. Plays back fine.
    Click solo on any instrument/folder/track and after a few bars it glitches badly. Audio stops and starts and the playback cursor jumps and stutters. Remove solo and it plays back normally. This is repeatable.

  2. Start a new project. One instance of Halion Sonic SE and a midi track with a simple 8-bar pattern. Plays back fine. Hit solo and after a few bars it glitches and skips. Unsolo and it plays back fine.

Additional info.
Installed C12 on a laptop in the studio attached to a MOTU M2 interface (USB3). That’s a different driver and interface and a different machine that was previously running C11 without a problem. The same bug appears when the demo project is loaded and any channel is soloed. After a few bars it skips and glitches. This would point to a problem in Cubase when Solo is activated.

Now I tried the same test on the main DAW machine in Studio 1, which has the same installation and is using a UA interface with TB3 connection. There is no problem with this installation. No glitches or skips with solo activated.

More investigation.
Back to the laptop. Tried a clean reboot. No change in the behaviour.
Installed the Yamaha ASIO driver for the UR12 and plugged that in instead of the MOTU M2, in case MOTU drivers were a problem. No change. The UR12 glitches and skips a few bars after solo is activated on any channel. I noticed that when the skipping occurs the HDD bar in the performance meter is all over the place, however all machines have dedicated SSDs for production projects and should not be a problem. Certainly not a problem when solo is not activated.

Another test, on Studio 1 machine. This is a large machine with the UA Apollo interface attached.
I put the Demo Pop Project on this machine and loaded it into C12. Soloing a track caused glitches and skipping after a few bars exactly in the same way as the other two machines that it was tried on. Unsoloing caused it to play back normally.

To compare I loaded up a large project (245 tracks with many plugins). It worked fine. No skipping or glitching when soloing any track. This track was created in Cubase 11, so I saved it as a Cubase 12 project and re-loaded. No problems, no misbehaving when soloing tracks.

Another test.
On the laptop, with the M2 interface. Soloing any track in the demo song causes glitching and stuttering after a few bars of playing in solo, returning to smooth playback immediately solo is deactivated.
So, as a test, I created a new empty project and imported all the tracks from the demo project. Set the tempo to 168 and played it back. All working fine. Soloing no longer glitches on this new version of the demo project, playback is smooth. No idea why, possibly an internal file format issue? The demo was obviously created on a Mac, and I am using a Win machine?


Could you test your system by using LatencyMon utility, please?

You didn’t specify any conditions under which to run this? Anything specific to monitor or perform when monitoring?

System 1 (Studio A DAW):
Result: Suitable.
Highest IPL: 113us
Highest ISR execution time: 128us
Highest DPC execution time: 290us
Total hard pagefault count: 91

I haven’t loaded on the other two systems but can do this if it appears to help.

For completeness I ran the measurement whilst Cubase 12 was running along with the demo project playing back and glitching when solo is used.

System 1 (Studio A DAW):
Result: Suitable.
Highest IPL: 400us
Highest ISR execution time: 317us
Highest DPC execution time: 631us
Total hard pagefault count: 2997

I didn’t notice any significant changes in the measurements between Cubase being idle and when running the project.
As I mentioned before, the system happily runs very large projects (over 1000 tracks in one case) using Cubase 11, and these projects work under Cubase 12.
The Demo Pop project, however, appears to trigger a bug when solo is used and the project stutters and glitches. Plays back normally as soon as solo is released.

Same problem here.

I changed from 32 to 64 bit float in system set up and that seemed to solve the problem.