Set default file associations

In Windows 10, the way to set the a default program or a file association is done with a .xml file and a Group Policy setting, when the computer is joined a domain – otherwise you do it manually.

Export

On a reference computer, setup the program and file association as needed and then export the result:

Edit

Edit the .xml file to  contain the settings you wish to apply to your computer clients. It is not recommended that you use it “as-is”.

Below is my default appAssoc.xml file containing Outlook and Internet Explorer as default apps on a computer.

If you wish  to add an Adobe product as default PDF reader, Adobe has created a ‘how to’ guide … Read it here

Copy

Now copy the .xml file to a network location where all your computers can get a hold on the file, eg. %NETLOGON%\ClientApps\appAssoc.xml

Group Policy

In an relevant Group Policy, go to [Computer Configuration], [Administrative Templates], [Windows Components], [File Explore] and select the [Set a default associations configuration file] setting. Enable it and hereafter enter the path and file name, of the location of the .xml file.

At next reboot the new program and file association should be effective.