Unable to start any projects due to apparent shader compilation bug

[Roy_Wierer.Seda145]

Related:

[Bug, probably] "Compiling Shaders", over and over again, but only in 4.27.2

Mostly solved, unclear how.

Might be worth checking if your disk usage is high because of another process, antivirus in particular. But the “compiling shaders” annoyance has been around since forever.