This policy setting controls whether Excel prompts users to update automatic links, or whether the updates occur in the background ...

This policy setting controls whether Excel prompts users to update automatic links, or whether the updates occur in the background with no prompt.
      
If you enable or do not configure this policy setting, Excel will prompt users to update automatic links. In addition, the "Ask to update automatic links" user interface option under File tab | Advanced | General is selected.
      
If you disable this policy setting, Excel updates automatic links without prompting or informing users, which could compromise the integrity of some of the information in the workbook.