“Outlook cannot open this item.” and tasks missing

Recently Microsoft Office Outlook 2007 started giving me the vague error message Outlook cannot open this item. The item may be damaged. The message would appear randomly throughout the day. Sometimes five error message boxes would be stacked up on top of each other.

OK, but which item? What kind of item? Is it an email, appointment, or task? One clue was my task list was empty. In the past, I’ve had problems with reminders showing up hours or days late (though I haven’t noticed that lately).

Someone in a forum suggested running Office Diagnostics. Diagnostics found and fixed something, but it didn’t give details. It didn’t help either. Thanks, Microsoft.

Then I found a solution for Outlook 2000 to run “outlook /cleanreminders”, but it does nothing in Outlook 2007.

The solution for Office 2007 is to run click Start, click Run, type outlook.exe /resettodobar, and click OK. Outlook will start, say “Loading” in the task pane for a few minutes, and then everything works again.

According to the Outlook 2007 command line switches documentation, /resettodobar “Clears and regenerates the To-Do Bar task list for the current profile. The To-Do Bar search folder is deleted and re-created.”