I started playing the sandbox puzzle. I took a break and can't now log in again to continue. Each time I click on the puzzle link in Contests, foldit is knocked off my screen completely and I have to log in again from scratch. I have tried this a few times now but no change.
Initially I had trouble logging in to this puzzle, and now I have the same problem Susanne has. Sometimes the puzzle will load but then simply crash within about a minute (and it's a weird crash because, as Susanne says, Foldit just vanishes from the screen and my operating system doesn't seem to realise that a program has crashed).
I'm looking into this.
This has been fixed and I'll post the update this afternoon.
An update has been posted that should fix this.