Do one of the following:

• If you are running Windows 10, choose Start > All apps > Windows System > Run > type Excel /safe in the Run box, then click OK.
• If you are running Windows 8, click Run in the Apps menu > type Excel /safe in the Run box, then click OK.
• If you are running Windows 7, click Start > type Excel /safe in Search programs and files, then click OK.

If the issue is resolved, click File > Options > Add-ins.

Select COM Add-ins, and click Go.

Clear all the check boxes in the list, and click OK.

Close and restart Excel.

If the issue does not occur when you restart Excel, start enabling your add-ins one at a time until does.

This will allow you to figure out which add-in is causing the problem.

Be sure and restart Excel each time you enable an add-in.