Do the following, as appropriate for your operating system:
Step 1: If you are running Windows 8, swipe in from the right edge of the screen, and then tap Search. (If you are using a mouse, point to the upper-right corner of the screen, move the mouse pointer down, and then click Search.) Type Run in the search box, and then tap or click Run.
If you are running Windows 10, Windows 7 or Windows Vista, click Start.
If you are running Windows XP, click Start, and then click Run.
Step 2: Type Outlook.exe /safe, and then click OK.
Step 3: If the problem is resolved, click Options on the File menu, and then click Add-Ins.
Step 4: Select COM Add-ins, and then click Go.
Step 5: Clear all the check boxes in the list, and then click OK.
Step 6: Restart Outlook.