Recurring restart pop-up while working with ArcGIS for Excel

Description

While working in ArcGIS for Excel, a pop-up displays, stating "Restart needed. Some updates must be applied to ArcGIS for Excel. Save, close and reopen the workbook."

This message may reoccur, even after dismissing it, and it may not be convenient to restart the computer.

Cause

This can happen after a software update when opening the workbook for the first time. This could indicate that ArcGIS for Excel's ribbon or tab didn't update correctly. Since the ribbon is set by the manifest, try clearing the manifest cache to fix the issue. 

Solution or Workaround

Follow the steps to clear the Excel Add-In cache in the following article: ArcGIS Excel tab is missing or showing up twice in the Excel Ribbon