Adding NumXL as Excel Trusted Publisher

Answer:

Adding the NumXL Add-in as an Excel Trusted Publisher can be done by following the steps below:

1. Click on the security warning message itself (not the “Enable Content” button).
   
2. Excel pops up the File “Info” screen.
   
3. Now, click on the “Enable Content” (with Shield icon) to drop down the menu, then click on “Advanced Options”.
   
4. Now, the Microsoft Security option pops up and reports one or two issues related to NumXL and NumXLUI (Toolbar Add-in). There might be publishers of other Add-ins in this list as well.
   
5. Although the NumXL Add-in is digitally signed, the publisher is not known by you. To work around this issue, click on “Trust all documents from this publisher.” and/or "Enable all code published by this publisher".
   
6. Repeat the same resolution for the remaining issues of publishers that you trust (if any), and click OK when you're finished.
7. Restart Microsoft Excel for the changes to take effect.