Troubleshooting

Clear your Office cache

If the add-in behaves unexpectedly, clearing the Office cache is often the right fix.

  1. Go to File > Options > Trust Center > Trust Center Settings > Trusted Add-in Catalogs

  2. Activate the checkbox Next time Office starts, clear all previously-started web add-ins cache., then click OK.

  3. Restart Excel

Alternatively:

  1. Close Excel

  2. Delete the following folder:

%LOCALAPPDATA%\Microsoft\Office\16.0\Wef

  • Close Excel via Cmd+Q

  • Run the following commands in a Terminal:

rm -rf ~/Library/Containers/com.microsoft.Excel/Data/Library/Caches/
rm -rf ~/Library/Containers/com.microsoft.Excel/Data/Library/Application
rm -rf ~/Library/Containers/com.microsoft.Office365ServiceV2/Data/Caches/com.microsoft.Office365ServiceV2/
rm -rf ~/Library/Containers/com.microsoft.Office365ServiceV2/Data/Library/Caches/com.microsoft.Office365ServiceV2/
rm -rf ~/Library/Containers/com.microsoft.Excel/Data/Library/Application\ Support/Microsoft/Office/16.0/Wef/

See also: https://learn.microsoft.com/en-us/office/dev/add-ins/testing/clear-cache

Addin xlwings Server failed to download a required resource

When installing the Office.js add-in, you get the following error in the taskbar of Excel: “Addin xlwings Server failed to download a required resource”.

Solution: Make sure to run your server via https, not via http by using TLS certificates. This also means that you will need to use a domain name, not the IP address directly.

The cell shows #NAME? or #BUSY! when using custom functions

Clear your Office cache, see Clear your Office cache