I've been seeing this off-and-on as well. Mostly c, yaml, python files. Plenty of disk space and the spill files are written to a separate directory (just for spill files). I've also closed all vs instances wiped the directory. After restarting several instances, and only 3-5 spill files, which weren't very big, I got the errors.
On a side-note, I have a 1M yaml file that makes vs grind to a halt trying to search. I have a feeling it may be related.