Was getting an annoying error message each time I opened Outlook 2010 running with Windows 7. Something about being unable to read the profile, whatever that is. I clicked cancel, got a beep sound, and from then on everything worked normally. After a few weeks of this, decided to just delete the profile, then add a new one. Like, how can that hurt things, it's just a name and email address, or so I thought. The good news - deleting the profile got rid of the annoying error message. The BAD news - I lost ALL my email folders, all my contact data, all my calendar data - EVERYTHING gone, replaced by empty inbox, empty contacts, empty calendar. No warning, no offer to save personal data in a safe place. I searched entire drive for the .PST files, they were nowhere to be found. Very scary. Years of accumulated data gone. If you're wondering whether I was running backups, the answer is an emphatic yes, until my external hard drive died, new one on order, not installed at time of this catastrophe. Fortunately, got everything back by running System Restore to an earlier date. Took 6 hours to complete, but at least it worked. You have been warned.