Microsoft Office access does not work to WebDav shares

Since Microsoft released a patch for Windows in Q4-2023, access to WebDav shares which use basic authentication is blocked:

Example

Example with ionos webdav share:

English: "Microsoft Office has blocked access to https://webdav.hidrive.ionos.com because the source uses a sign-in method that may be unsecure

German: "Microsoft Office hat den Zugriff auf https://webdav.hidrive.ionos.com blockiert, da die Quelle eine Anmeldemethode verwendet, die möglicherweise unsicher ist."

 

Solution

To fix this, you have to add the following registry key to Windows 11 with the URL to your destination (in this example it is webdav.hidrive.ionos.com):

[HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Common\Identity]
"basichostallowlist"="webdav.hidrive.ionos.com"