Cubase 12 64 bit crashes every time I open key editor

Hello. I haven’t found a solution that works for this problem & can’t use MIDI as a result.

Whenever I try to open the key editor, Cubase 12 freezes & I have to use task manager to close it. This has only just started happening. I’ve uninstalled all recent plugins & moved (not deleted) the User Settings folder as was suggested in this forum, but the problem persists

I’m using Windows 11.

Any ideas please?