When BitComet starts up and tasks begin in hash-check mode, it means that something made BitComet shut down before it could flush its buffer to disk. All of the tasks that were running are therefore in an unknown state and BitComet must reassess the files to learn what state they are actually in. (Very bad idea to interrupt this process, btw.)
That’s usually caused by a system crash.
We can all hope that Microsoft has at last learned to handle problems more gracefully than the BSOD. They have assured me that this is so. They told me when they first released XP – no more crashes, no more BSOD’s. I’m sure it’s just coincidence that Windows’ default behaviour is to automatically restart after a crash, which covers up the evidence of the crash.
So if you believe Microsoft about this, I have a wonderful bargain for you.
Something catastrophically interrupted BitComet. You say it’s not a system crash.
Ok.
Then you need to look at the system and application logs, and find out what it was.
It would be nice if windows DID behave better after a crash, re-opening all of the apps that were open, generally putting you back where you were when the crash occurred instead of putting you into the “just rebooted” state. Does Win7 do this, at last? Maybe. If it does, then it would re-open notepad, etc. (It’s the way Windows should have behaved starting fifteen years ago.)
I would not take this as evidence that it didn’t crash, so certain and sure, that I wouldn’t bother turning off automatic restart because I know better and it couldn’t be that. If it isn’t, you haven’t lost anything. If it is, you’ve learned something. And as Will Rogers observed, “It ain’t what you don’t know that’s the problem, It’s what you do know, that ain’t so.”
Whatever you do, you need to figure out why your system shut BitComet down this way.
Having torrents merely stop downloading is an entirely different matter, not the same issue at all.