Game boots up fine. I select my character and start Heading Into Town... then I get an endless black screen. I can't click on anything, I can't relog from within the game, I can't go to town. There's just a black screen and the title music is playing.
I'm playing through Steam and am able to access the Steam Overlay. I can also press ESC to access Spiral Knights' options window. The only way to get out of this is to ALT+F4 or somesuch.
I had this problem once earlier today after patching. Fine. I verified game files through Steam. That didn't fix it.
Rebooted computer. That didn't fix it, either.
Left it alone and went to do other things. Came back this evening, and there's another patch to download. Get that, and what do you know, I can play again.
Didn't use all my Mist, quit out so I can get something done, then try playing SK again. Black screen again. Previous "solutions" still don't work, symptoms are the same.
This all started today and there have been no major changes to my setup apart from the updates to Steam itself.
Windows XP, Steam
I just encountered a similar problem with entering the ATH. My character loads in Haven [15 and 17; two different tries] and can access the Bazaar without issue, but cannot seem to enter the Advanced Training Hall. On both occasions that I've tried, I've gotten a black screen.
If it helps at all, I have a MacBook and I play SK through the download, not Steam.