Can't activate playback no matter what

I’ve been stuck with this for hours. I think it may be related to the 6.2 update I tried to install, or to Windows Defender deciding it doesn’t like the VST audio process today. Every time I try to activate playback on a project, it just freezes for some seconds, and then immediately goes back to being inactive. I’ve tried changing playback templates, using the default one, restarting PC, reinstalling Dorico, etc. Is it because there’s too many instruments in the project?

Hi @sjmmusic , welcome to the forum.

As a first approach it is best if you post a diagnostic report. Therefore load a projecdt and try to activate it and after the freezing choose from the Dorico menu Help > Create Diagnostic Report. The corresponding zip file please send to u dot stoermer at steinberg dot de
From the contained logs and things I will then be able to come up with more advice.