In order to fix the issue, go to Start > Control Panel > Uninstall a program, select the Office Suite from the list and click the Repair button next to Uninstall. Follow the on-screen instructions, reboot your computer and try again. If it doesn't help, try disabling your Outlook add-ins one by one. From the Tools menu, click Trust Center, and then click Add-ins. Uncheck the box next to each plugin, click OK and try again. If none of these help, perform a full system scan using your security program, run a registry cleaner from the Software Informer database, close all unnecessary applications using Task Manager and try again.
