Cubase 9.5.10 hangs - solved

I have been having major hangs since I upgraded cubase to 9.5.10. There were some hangs in 9.0 also, but nowhere near as many. Cubase would just stop; no windows could move. The rest of the PC appeared to be OK but one CPU was pegged to cubase. I would stop cubase in task manager open it again and within 5 minutes it would be hung.

I have tried everything over the last few days: I changed video cards, switched audio interfaces, upgraded drivers, switched memory sticks, all sort of stuff and nothing changed it. Some projects seemed to be OK and would run for hours, others hung quickly. I tried 32/64 bit, ASIO-Guard. Nada.

Finally, I found something that affected it: When any plugin with a VST version of 3.0.2 or below has a sidechain input, that causes some sort of corruption to ASIO. Eventually (sometimes quickly) that corruption causes an ASIO fault, which manifests as the process looping on I/O and not responding to anything else.

Switching all plugins that use sidechain INPUTS to be VST3.5+ and it is as stable as a rock - has been for hours, across three reboots, not a glitch. All of the UAD plugins are VST2.4, sadly, and I have a few Waves plugins that are VST3.0.2. I guess I will be upgrading these asap.

Hope this helps someone. I raised a case with Steinberg, but it’s not really their problem, and I am just glad I have a stable system again.

It is not 100% stable - some older VST plugins also cause hangs, but sidechain inputs appear to need very latest VST3 revisions in this version of cubase.