WebDAV + MS Office - request login/password every time on open documents

When open MS document from mapped WebDAV disk, MS Office ask request login/password every time on open documents.

Nextcloud version 13.0.
Operating system and version: CentOS 7.4
Apache 2.4.6
PHP version 7.0.27

The issue you are facing:

Is this the first time you’ve seen this error? Y

Steps to replicate it:

  1. Install
  2. Try to use mapped WebDAV disk with MS Office

Had the same problem a while ago. I guess Microsoft is not able to comply with the RFC standards for webdav, but that’s just a wild guess :wink:

I suggest you to use https://mountainduck.io/ to work with MS office documents across webdav in Windows file explorer, it works great.

Good luck, cheers zisuu

But “Mountain Duck” is not free app…

If you dont wanna spend money, try https://cyberduck.io/ instead.

Did you open a support request with Microsoft?

No. To me it seems it’s pointless.

I can confirm that Microsoft WebDAV (aka Webclient Service) is not capable to connect with modern secured TLS WebDAV servers. The culprid seems to be SNI. The curiosity: With older versions of Windows (WinXP and Win2003 Server) WebDAV works but only because MS is not checking certs and encryption. Since 2009 with introduction of Win7 they broke their Webclient.

Bottomline: With Windows and WebDAV you’re using an unsecure and not standardized solution. Use Nextcloud Client App or other WebDAV solutions. I suggest Onlyoffice or Collabra running in Webbrowser.


The whole sad story with Microsoft, Office and SNI diggs a bit deeper.

Recently I was called by an admin who tried to get his ActiveSync work with Microsoft Exchange server behind a reverse proxy I set up for this customer. The reverse proxy worked well, all mobile devices were connected and Outlook Web Access (OWA) in Webbrowsers worked as expected. But not the Microsoft Outlook Fat-Clients. The culprit here was SNI and modern TLS encrpytion, again. Microsoft fails to support basic RFCs in his main products Windows (WebDAV) and Office Outlook (ActiveSync).

“but it worked with my previous employers’ exchange server” the admin said. “Well then let’s examine this server”, I’ve responded and checked this server with SSL Labs. Our discussion stopped instantly after this…

Bottomline: Microsoft sucks… and a poor guy will get a lot of work soon…

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