I know i saw this problem somewhere. When someone tried to save their map, and when they loaded it again all the brushes were gone. (not hidden... deleted). Anywho, the persons solution was to load up the autosave (unless it was overwritten already) :( Well i've come across the same problem on a map i've been workin on for weeks. But i can't find the location of the doomedit autosave :( I've been in and out of the doom3 folder with no luck. Someone helpme cause i'm sadface :(
Please ignore this post. I've found the location. But for future reference it was saved to my C: Drive.