Thanks for all the replies. Two things 1) i have not read anywhere what files to exclude for chrome all the talk is about is about safari. i have also read that time machine would keep some info about browsing with chrome even if chrome history was excluded so that is not an option. going back to turning off time machine manually can i rest assured that with time machine off it is fully unoperable and is not backing up any files, web useage or anything else. some reports say it continues to work even when the slider is in off to some degree even if not fully?