Fix for black screen on Windows 1909 or newer
This fix is so important for a lot of people that I feel like posting it on the wiki for everyone, even though it's not Linux-related (but it is open source software-related). Linux users do not need to go through these steps.
For Windows 10 1909 or newer:
Open Settings and search for "Graphics Settings". Select "Classic App" and browse to C:\Program Files\obs-studio\bin\64bit\obs64.exe (or wherever you have installed OBS). Click "Options" (example screenshot).
If you want to use display capture to capture your screen / desktop, select "Power Saving".
After you've done this, restart OBS. Then in OBS go to Sources - right click, Add > Display Capture > OK > you should no longer see a blank screen > OK