I have a user that has a laptop. A new hard drive was installed. When we pull down this users back up and go to their outlook, the files have .ost extensions instead of .pst. We cannot import the file with this users email. I read that the same account has to be installed in Outlook to be able to open this backup file. Is that true, and how do I import through Outlook, there is no choice to import a .ost file. It is Windows 7 with Outlook 2010.