Set Custom File Extension For W10

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I haven’t done this yet, but I wanted to take notes for when I do this. Follow this guide to set custom file extensions in Windows 10.

To Resolve:

1. Setup computer the way you want

  1. Run:
dism /online /export-defaultappassociations:"C:\Temp\IE-DefaultBrowser.xml"

NOTE: DO NOT delete lines from this.

# This didn’t work, what DID work was:

Dism /Online /get-DefaultAppAssociations >C:\TEMP\DefaultApps.txt

# Then just rename to XML.

  1. On new computer:
Dism.exe /online /import-defaultappassociations:c:\temp\CustomFileAssoc.xml

# Your file will be copied in \Windows\System32 with the following name OEMDefaultAssociations.xml

  1. Or through GPO:

Configure the following policy Set a default associations configuration file located in Computer\Policies\Administrative Templates\Windows Components\File Explorer.

If this group policy is enabled and the client machine is domain-joined, the file will be processed, and default associations will be applied at logon time.

To control only some extensions, see the reference.