As the title states, starting from version 17.1 AE locks up any and all parallel media playbacks on my Windows machine. Version 17.0.6 works fine.
This means that I can not play any audio or video files in external software when After Effects is running.

They simply freeze.. UNTIL I play the timeline in AE, then the drivers unfreeze and playback of media outside of AE resumes.
Even in browsers this is the case. A youtube video actually pauses and plays in sync with starting/stopping playback in AE.
I have the latest version available for Windows and NVidia and Steinberg (Audio) drivers.
This behaviour is very limiting to my workflow.
The issue occurs when Media Core is loaded when booting up AE.
I have tested it with no plug ins and extensions active. I have reinstalled multiple times ( Also to check from which update this happens). Preferences don't seem to be part of the problem either.

All I can say is: What the ...?
Windows, Ryzen 1700, 32 Gb Ram, GTX 970, UR 44 audio interface