Hi mrs.von, does the workaround in the following thread help:

https://support.mozilla.org/questions/1265375#answer-1239993

We tried that before I posted here and that unfortunately doesn't work either. Several users tested this. This wasn't a problem until recently.

To clarify, when selecting the link, Firefox adds the following to the front of the actual link in the URL

ms-word:ofv|u|https:// or ms-excel:ofv|ofc|u|https://

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.

I have had this problem for a couple of months. The message I get is the same. I have uninstalled, reinstalled and tried countless suggestions. Sadly I have to stop messing with this and switch to another browser which is upsetting to me as I don't like to use microsoft or google. This is really frustrating.

As it turns out you can no longer sync folder with Microsoft OneDrive either. The URL adds the following: odopen://sync

This makes Firefox unusable for Office 365. A real real shame.

I have checked with Microsoft and they said there is nothing they can do about this. If this is not fixed then Firefox will render useless for hundreds of thousands of work devices.

I am having the same issue. Removing ms-word:ofv|u| as indicated above by mrs.von downloads a copy of the file and does not permit co-authoring in the documents.

There are workarounds (e.g., opening the document in the browser view, then opening Word to access the file through the recent documents), but these are time consuming and impractical. Looks like there's an issue with how Firefox handles these links.

As indicated above, if this is not resolved, I will have to switch to a different browser for business use.

Hi Valerie, did you already set up the new preference as described in this post:

https://support.mozilla.org/questions/1265375#answer-1239993

Having the same issue - going to have to switch browsers. This is really frustrating....

Is there any update from Firefox on whether or not this problem will be resolved in the near future? I have the same problem. The solution above, doing the about:config thing, pasting in "network.protocol-handler.external.ms-word" and making sure it says "true" worked at first - i.e. when I started to have this problem last summer or so. It worked a few times, but it is no longer a solution. When I go to about:config for both Word and Excel it is already "true". Sad to leave my favourite browser.

On Windows the protocol needs to be added to the Windows Registry (HKEY_CLASSES_ROOT) by the application that support it to make it possible for other applications to find and use it.

cor-el said

On Windows the protocol needs to be added to the Windows Registry (HKEY_CLASSES_ROOT) by the application that support it to make it possible for other applications to find and use it.

Check, Windows Settings -> Apps -> Default Apps (on the left) listed under the Reset button, you will see

• Choose Default Apps By File Type
• Choose Default Apps By Protocol
• Set Defaults By App

Select *Choose Default Apps By Protocol (it may take a minute for the list to load) find the Protocol and click on the line to the right of it to select an app.

Hello,

I have struggled with this issue a long time and found the solution. Hopefully this helps others.

The problem for me was that in the past - longtime Firefox user here - I had already set some associations in Firefox which made it handle Office files coming from our Office 365 sharepoint wrong.

What I did first was set all the application handlers back to default.

1. Go to options 2. Scroll down to Applications 3. Make sure all the application handlers for Office files are set to default and not another entry. See my screenshot example for Word.

Then I added all the know URI schemes for Office manually to Firefox based on this documentation: https://docs.microsoft.com/en-us/office/client-developer/office-uri-schemes

1. Type about:config in your address bar 2. Type network.protocol-handler.external.ms* in the search bar 3. Add the missing network.protocol-handler.external.ms entries you miss, compared to the screenshot.

Restarted Firefox and it now opens all files clicked from a sharepoint online link correctly now.

I hope this helps all other frustrated office users.