Map loading problems (freezes or dumps back onto main menu)

Yesterday Garry’s Mod was working fine but today it’s suddenly turned uncooperative; whenever I attempt to load a map (either from a mounted game, a workshop, or local addons), about half the time it locks up completely and the other half it just dumps me back on the main menu after a minute or two. (Neither of them produce crash dumps, and I can’t open the console to see if something went wrong with loading the map.) I uninstalled all the addons, put graphics on low and even tried pushing it onto the beta, but it’s not fixing it. Does anybody have any other suggestion of what I can do to fix it?

Well something happened and it spontaneously resolved itself, so I marked this as resolved.