–Ignore this thread, solved the problem!–
So it suddenly started happening…
A few days ago I fired up a server with hamachi, 3-4 of my friends could join the Gmod server without problems, others crashed at “Sending Client Info”
I wondered alot and looked in my addons what could have been wrong, I defragged Gmod, still nothing happent, and verified the game cache files.
Result? Not working. Still crashing.
So the first thing I thought could be possibly wrong was my Gm_mount2, since it had alot of problems through all the Gmod updates. I deleted my Gm_mount2.dll which is supposed to disable Gm_mount2 as read in the Readme file of the addon. And of course I used the SVN version.
I let some of my friends to join again, same friends could join again, and same of those who couldn’t, couldn’t join now either.
Yesterday I was bored and messed around in singleplayer and got an invitation from a friend to join a clan server to have some fun, crashing at Sending Client Info when the loading is almost done.
I verified the game cache files again and defragged the game. Still nothing that works.
Need help, and fast!
Found someone with the same problem: http://www.facepunch.com/showthread.php?t=965237