[SOLVED] OT: Win 10 april update broke recording

[Marvin]

Hi,
We updated two Win 10 machines at work, to the april 2018 update. Since then, I can't record audio. Playback works fine, the sound cards seem to work, but when I press "Record" I get error messages.

I've tried different sound cards (Focusrite Scarlett 2i2 usb, M-audio delta 44, both worked fine before (completely uninstalled one when testing the other)) and different audio programs (SAW Studio, Hindenburg, Audacity).

I get a signal in the M-Audio control panel, but still can't start record. The error message differs between programs, but something like "cannot initialize sound card. Check device settings".
I've set programs and sound cards to 16 bit, 44.1kHz. In Windows sound settings, it's also set to 16 bit, 44.1kHz. As I said, playback works fine.

I did a rollback on one of the computers, and then it worked again.

Does anyone have a clue?