Like OP, I've also had this since forever (more than 10+ years now?)
Sonar crashes; this happens randomly at random times, its not a plugin or a WoW or thing I'm doing, but it stays in memory until I try to "force close" it from Task Manager. Most of the time Sonar will restart. Otherwise I must reboot.
I've brought this up over the years here, but never got a final answer on it.
I think this is still hardware driver related. I believe this is still the M-Audio MIDISPORT 8x8 driver, although it also might be the NI Maschine hardware driver. I don't think its RME drivers as I've never seen them stuck.