I upgraded 2 weeks ago from windows 8.1 it took about 1.5 hours no probs but slightly quicker all round, only prob I have is it doesn't want to recognise my Microsoft office 2003, but it can be made to work with office 2003. on the whole it appears to be alright. I also upgraded a 10year old laptop from windows 7 ( it was originally XP) and it works its a bit lumpy, when streaming from the net but it does ok as a backup. hope this helps