This has been documented numerous times over the last 18 months with no definitiive resolution. All resolutions I have tried have only been temporary. They work for a little while. Does anybody know why MS Outlook 2007 does not run reliably under Windows 7 Professional? Why does it stop responding? It seems to be related to communicating with a mail server. If it is offline it works fine, but when it's offline, it's not really doing anything. I have replaced .dat files, deleted and re-established an account, removed the hotmail connector, but Outlook won't let me disable add-ins as it says it must be done by an administrator. I am the administrator and only user on my computer. What gives?