I have the same problem periodically. Its very annoying as I am OK for a while and then it progressively gets worse until I have to refresh. I am using Outlook offline and its my offline folder that gets corrupted. I can fix it temporairly with scanpst, but eventually it becomes unfixable. To fix the problem I go to my offline file, which is called outlook.osf. It can be found typically at C:\Documents and Settings\"username"\Local Settings\Application Data\Microsoft\Outlook. After closing Outlook, I rename the file to outlook.old. I then bring Outlook up in online mode and do a send/receive all, which rebuilds the osf file. I have a CRM package that also syncs to Outlook and wonder if that causes the issue or BDM itself. If anyone has any words of wisdom, it would be much appreciated.