How to configure mailto for everyone

Posted by nodiaque@reddit | sysadmin | View on Reddit | 8 comments

Hello everyone, We have some user that when they click a mailto link, it open edge instead of outlook. We know how to fix it directly in the gui but we want to be proactive. I know about the xml association file, which was already fixed to have the proper value. Problem is this is applied only on the first logon. I know I can deploy that xml from GPO but this will override any change the user make, which is not what we want. I looked at the good old way of changing the registry and now, those key have a hash that protect them from alteration. Even when doing a copy/paste of the value on the same computer, it doesn't work. Is there another way to apply a protocol association that we could run oneshot for everyone? Windows 11 25H2 Enterprise Thank you!

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8 Comments

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St0nywall@reddit

The only reliable way for Windows 11 is the XML appassoc. Here is a link showing you how to do it. [https://learn.microsoft.com/en-us/troubleshoot/microsoft-365/admin/group-policy/configure-email-client-using-policy](https://learn.microsoft.com/en-us/troubleshoot/microsoft-365/admin/group-policy/configure-email-client-using-policy) Instead of using a GPO, you can run a script that launches the DISM command for the user to import the XML file. The benefit of that is you can check for a registry flag to validate running the command or not to run it. I would check if Outlook is installed AND if the mailto is not set to outlook then run the command. Check `HKEY_CLASSES_ROOT\mailto\shell\open\command` to see which executable is handling mailto links.

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nodiaque@reddit (OP)

Thanks for the reply. Like I already said, the xml appassoc isn't an option. Why? It only apply to new user login for the first time [https://learn.microsoft.com/en-ca/windows-hardware/manufacture/desktop/dism-default-application-association-servicing-command-line-options?view=windows-11](https://learn.microsoft.com/en-ca/windows-hardware/manufacture/desktop/dism-default-application-association-servicing-command-line-options?view=windows-11) https://preview.redd.it/c8o4gxrg6yzg1.png?width=751&format=png&auto=webp&s=da75d45bf030d1138033d5f22f92af3e2063d4a3 The xml was already applied to fix, but we still have user with the defective file association since the userprofile was created before.

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St0nywall@reddit

In that case you will need to use the GPO method for per-user or you can try [SetUserFTA ](https://setuserfta.com/)to set the file association.

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nodiaque@reddit (OP)

I did found out something that is documented only in the GPO. Might be a new thing in a recent administrative template. In the xml file, only for the GPO, you can put 2 things. The first is a version and the other is suggested="true" for any association. When it's suggested, it will be applied once per version, which mean until you increment the file version again, it won't reapply this. Very handy and fix my problem. Can't find anywhere on the MS documentation online that explain this.

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St0nywall@reddit

The suggested-true will allow the end user to make changes to the default association. Without that it is locked to what is in the file.

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nodiaque@reddit (OP)

No entirely. Without the suggested, it is reset each login but user can still change. I don't mind if user change it, but I at least want the default one to be properly set, which is not the case currently.

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skydiveguy@reddit

I literally just did this last week for our org.

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Adam_Kearn@reddit

GPO is the only easy way todo this You can do a logon script but then it gets a bit dirty with powershell scripts and reg hacks to make it work