IGN is same as here, connected to my Steam account.

The game launched normally and just fine earlier today but when I went to launch it a second time, it brought me to a non-Steam login screen despite launching Spiral Knights from Steam. I tried validating files and it did find 10 unvalidated, downloaded but didn't fix my problem.

Things I have done...
Validating files. Validated once with 10 failing to validate, downloaded them and tried again. Problem still exists.
Validated files again. 9 files failed to validate, tried an uninstall/reinstall and tried again. Problem still exists.
Checked Java version; it is up to date with the most recent version.

Any other ideas?

Edit: Annnd it seems Steam was the problem itself. Rebooted Steam and it appears to be functioning just fine. Ah well, probably needed an uninstall/reinstall if files refused to validate. XD