So I tried to start my server, it got to executing dedicated server config, then crashed with a debugger with that error, “Illegal termination of worker thread! Threads must negotiate an end to the thread before the CThread object is destroyed.” It sounded like a module problem, but I hadn’t installed any modules. After a while, I figured out that a quick fix is navigating to orangebox/garrysmod/cfg, and deleting a file in there called gmod_cvars_sv.txt.
I don’t know why this works, but after you delete it, your server should start up normally. The only problem is, that file likes to come back again, and again, and again… so if anyone has a better fix than this I would be appreciative.