This problem has been going on for me - for just over a month now, not on Outlook, but with the newer Windows Live Mail.  After going on and off for a couple of weeks - I switched to Mozilla Thunderbird and that worked for just over a week - now it too has the same problem.  Lots of calls to tech support in India, the Philippines, and the U.S.  NONE of them have been able to help BUT - for the first time tonight a guy in India told me that they have been getting so many calls on the subject that the supervisor is now requiring them to write down how many they get per shift!   HA!   I'm afraid we're in for a LONG wait on this one.