Either the file is corrupted or is already open somehow, but everytime I launch Outlook I get an eror message that says, "An extension failed to initialize. can't open file: extend.dat. the file may not exist, you may not have permission to open it, or it may open in another program." I have re-installed outlook, I have checked folder permissions and that doens't seem to be the problem. I also performed a system search and the file is not in the folder it should reside in. Is there some way to either download this file from microsoft or can someone shed some light on fixing this problem for me? Any insight is appreciated.