yo how come in garry's mod when i try to upload my thing to hammer, hammer always freezes?? the first time i did it it worked but now it doesnt!!
dont know maybe your running too much and your computer cant handle it.well thats probally it.Maybe something else though.
The best way to map doesn't involve Garry's mod.
Try to reinstall it* i had that problem to but then i reinstalled it and it was ok :)
well did what Mentalx said work?