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non pervasive change to applications/actions

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Hi read your article https://support.mozilla.org/en-US/kb/how-to-fix-preferences-wont-save

I have changed the action for content type "mail to" to my default email app outlook. Despite this when I click on an embedded web page mail to link, the action reverts to the new office "mail" app which I do not want. When I get to the section in your article "User.js file overriding Firefox settings" as the next step in trying to fix the issue, and follow the instruction "Click the Firefox menu - and select Exit." then I am thrown out of the dialogue, it is not logical. Please advise as I don't even know if the user.js is causing the persistence?

Thanks Andrew

Hi read your article https://support.mozilla.org/en-US/kb/how-to-fix-preferences-wont-save I have changed the action for content type "mail to" to my default email app outlook. Despite this when I click on an embedded web page mail to link, the action reverts to the new office "mail" app which I do not want. When I get to the section in your article "User.js file overriding Firefox settings" as the next step in trying to fix the issue, and follow the instruction "Click the Firefox menu - and select Exit." then I am thrown out of the dialogue, it is not logical. Please advise as I don't even know if the user.js is causing the persistence? Thanks Andrew
Attached screenshots

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Hi there, Thanks this was helpful. It turns out that Microsoft does its usual and trumps firefox settings. When I discovered your advice to go thru "windows/settings/apps/defaultapps/mail" - there are four settings:

1 .eml

I don't know what this does. This was already set to the target "outlook" and therefore ok

2. Mailto

This was set to "mail" and I changed it "outlook". I then tested an embedded web page and this now works correctly

3. MS-unistore-email

I don't know what this does. This was set to "mail" and when I tried to set this to the "outlook" target it was not an option, the dialogue forced me to visit the microsoft store where outlook had to be searched for, and then it invited "install"...curious given that I already have outlook, I suspect it does not recognise that I have office 365!

4. Outlookmail

I don't know what this does. This was set to "mail" and when I tried to set this to the "outlook" target it was not an option, the dialogue forced me to visit the microsoft store where outlook had to be searched for, and then it invited "install".

In summary clicking embedded mailto links now works as it should. PS I would have attached screenshots but another feature of microsoft's ecosystem is that it turns out I cannot screen shot a system dialogue screen.

Many thanks lads for your help Andrew

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Start Firefox using Troubleshoot(Safe) Mode {web link}

A small dialog should appear. Click Start In Troubleshoot(Safe) Mode (not Refresh). Is the problem still there?

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Hi Fred, I'm afraid after trouble shoot the mail persistence issue remains

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Hi Andrew, just to clarify, Firefox uses your mailto handling preference on the Settings page for two actions:

(1) Clicking a mailto link in a page (2) Use the Email Link feature (there is an optional toolbar button for this, or it can be found on the Alt+F File menu)

If you use the newer Share feature (for example, right-click the tab and click Share), Firefox calls the Windows 10 Share dialog, which may have its own priorities that are beyond Firefox's control.

And of course, Share buttons in web pages may lead to other options...


If the problem affects one of the first two features I mentioned, could you compare the settings when this happens, in the dialog described by this article:

Change the program used to open email links

Does that setting changing from "Use Outlook (default)" to "Use Mail (default)"? That would imply that the system default has changed, which would be odd. Or does the dialog indicate that Outlook is still the system default and it changed to Mail anyway. (?!)

The user.js file doesn't affect application handling preferences. Those are stored in the handlers.json file. Normally that file is not modified or removed by "cleaners" you might have on your system, but if it is, it normally would change only between sessions (start/exit cycles) or between system startups, and not in the middle of a session.

You also could check whether you have any active Enterprise Policies controlling your Firefox settings. Type or paste about:policies in the address bar and press Enter to load that page. Normally, the Active panel just says "The Enterprise Policies service is inactive." Does yours indicate anything else?

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Chosen Solution

Hi there, Thanks this was helpful. It turns out that Microsoft does its usual and trumps firefox settings. When I discovered your advice to go thru "windows/settings/apps/defaultapps/mail" - there are four settings:

1 .eml

I don't know what this does. This was already set to the target "outlook" and therefore ok

2. Mailto

This was set to "mail" and I changed it "outlook". I then tested an embedded web page and this now works correctly

3. MS-unistore-email

I don't know what this does. This was set to "mail" and when I tried to set this to the "outlook" target it was not an option, the dialogue forced me to visit the microsoft store where outlook had to be searched for, and then it invited "install"...curious given that I already have outlook, I suspect it does not recognise that I have office 365!

4. Outlookmail

I don't know what this does. This was set to "mail" and when I tried to set this to the "outlook" target it was not an option, the dialogue forced me to visit the microsoft store where outlook had to be searched for, and then it invited "install".

In summary clicking embedded mailto links now works as it should. PS I would have attached screenshots but another feature of microsoft's ecosystem is that it turns out I cannot screen shot a system dialogue screen.

Many thanks lads for your help Andrew