Error in Firefox when opening Word or Excel files - The address wasn't understood

Frequent Contributor

When opening documents from SharePoint in Firefox the following error message appears:


The address wasn't understood

Firefox doesn't know how to open this address, because one of the following protocols (ms-word) isn't associated with any program or is not allowed in this context.

You might need to install other software to open this address.


Unable to open Word and Excel documents from within SharePoint. This has never been an issue until recently. The documents should either open in the browser or trigger the desktop app. Installing older versions hasn't fixed this.

When selecting the link, Firefox adds the following to the front of the actual link in the URL


And the page with the error messages appears.

When removing ms-word:ofv|u| or ms-excel:ofv|ofc|u| the links work and do as expected. This happens on a Mac and PC / Firefox only.


Opening documents from OneDrive do not trigger this error, this is SharePoint only.






3 Replies
Unable to sync folders too. URL starts with odopen://sync and same error message as above appears.
Anyone else able to replicate this?
We have more and more users complaining about this. Thanks

@Philine von GuretzkyYou need to tell firefox to use NTLM authentication for the site that is giving your users problems.


1. Open firefox

2. In the URL bar, type "about:config"

3. Click "I accept the risk"

4. Search for network.automatic-ntlm-auth.trusted-uris and double click it

5. In the text box that opens, type the domain name of your site.  

6. Click "Ok"


I hope this solves your issue!