QuickTime recordings turn solid green

thanks for the info. sorry, I'm kind of stumped. it sounds like it was working prior to an upgrade, yes? but if it was working as expected in an earlier macOS, you could use an external SSD and install the macOS on it that your gear was working with prior to the upgrade. then boot into that drive when you need it. so if your Mac can support the earlier macOS, you may want to try that. it is not an ideal solution, but it works. it is what I did to run a piece of hardware that the vendor ended support for anything after Catalina.

it sounds like it may be a DRM issue. what exactly are you recording? also, what are you using as your "save to" location? and if you are recording via safari, maybe try a different browser. like Firefox.

OK. then which connections are you using? (ports, cables etc) and are any drivers in use?