1. Click "Start," then "Run."
2. Type "regedit" (without quotes) and press "Enter." The Registry Editor will appear. The nested folders in the left pane represent registry "keys," and clicking on a key will bring up one or more editable values in the right pane.
3. Navigate to the "Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office\Outlook\Addins\" key and click on it. A list of Outlook add-ins will appear below.
4. Find the add-in that's causing the problem. This may require some trial and error, but you can make an educated guess: This problem is known to be caused by various Norton security add-ins and also by the "eDataSecurity" add-in sometimes installed on Acer computers.
5. Disable an add-in by clicking on it, then double-clicking on the "LoadBehavior" value in the right pane. Enter a zero in the "Value data" field and press "OK." Close the Registry Editor.
6. Click the Start Menu and navigate to the following path: "All Programs" -> "Microsoft Office" -> "Microsoft Office Tools" -> "Microsoft Office Diagnostics." Follow the on-screen instructions to run Microsoft Office Diagnostics. This utility will repair the Outlook configuration files damaged by the add-in, and since you disabled the add-in above, the files will remain healthy. When the Diagnostics process is complete, Outlook should run normally.