Using Windows 7 with Windows Live Mail, which receives mail from my ATT account.  Error message:  "Windows Live Mail could not be started.  Your calender contains corrupt data that is forcing WLM to close"....I checked the ATT email calender via its internet access.  I do not use the calender on the ATT email account, and it is blank.  Removed and reinstalled WLM.  Same error.  No problem accessing email via internet portal.  Thanks for help.