Lately I've been having problems with the game not starting up at all. It gets as far as the window opening up with nothing in it, then closing again a few seconds later. Sometimes I'll try a few hours later and get on no problem, then I'll close the game and try again later and it'll be doing this again. Friend said it had something to do with a failed patch and that he had the same problem too.
I have tried reinstalling Java (and it is the latest Java), and reinstalling Spiral Knights. My graphics drivers are up to date and I have no problems running anything else.
Sometimes with a Steam install you may need to manually delete the contents of your
.../Steam/steamapps/common/spiral knightsfolder before a reinstall will work properly.