I have a user that since yesterday morning has been having random "An internal error has occured" errors and Adobe Reader X crashes out. He tells me that it doesn't happen on every PDF he tries to open and on the ones that it does happen if he keeps trying to open the file it will eventually work. Though when it does it might not display properly or it will cause Reader to freeze. In his words, "It's not always the same result with each file."
I've been reading around at all the 'internal error' threads (seems fairly common!) and it seems that it could be something nice and simple from a permissions error, which I can't see it being this because then it wouldn't work at all surely? And then there is complete hit or miss fixes like reinstalling or a reg fix!