Hi folks, GHCi has some weird behaviour sometimes with one or more of these symptoms: - becoming very slow and/or unresponsive - gobbling up memory - crashing with "thread blocked indefinitely on MVar" Some people have reported this happening when they weren't even doing anything, GHCi was just sitting at the prompt. e.g. this ticket: http://hackage.haskell.org/trac/ghc/ticket/4245 All the reports were Windows, but I've seen it happen on Mac too (but not Linux). I really need a way to reproduce this. If anyone has any clues, or can offer any more information (even if it's just a "me too, on platform X"), please let us know. Cheers, Simon