Strange problem with Guitar Bus

A couple of weeks ago I mixed project more or less satisfactorily in Cubase 13. As usual, I fed two guitar tracks into a “Guitar Bus” so I could apply a little volume automation (ducking during the vocals) All was good.

Today I load it to review it. The guitars completely drop out for a few seconds at multiple places at random (but consistently repeatable). They are sometimes (but not always) replaced with a kind of white noise hiss which fades out in different ways. I checked the original wave files and all is good. I checked the automation and the automation line is good - just a little lower during the vocals as intended.

Eventually I routed the two guitar tracks direct to Stereo Out and all is good again! So there is something funky/corrupt with the Guitar Bus where the simple automation is.

I guess I can delete the Guitar Bus and redo the automation from scratch - but this seems like a bug to me. I have rebooted the computer , re-installed Cubase and opened the original project many times - and it always drops out on the Guitar bus exactly as above.

Has anyone experienced anything similar? I am really worried that I might open another project with much more complex automation on some other Buses and it will also be screwed.

Cubase 13.0.30 Pro on Windows 11.

Could be a plug-in in trial mode.


Wow - you nailed it ! Thanks.

I recently had to reinstall Windows etc and everything else - forgot that plugin license on the Guitar Buss… The plugin should have not worked at all or throw a warning, imho rather than spasmodically work.