You may have noticed that sometimes, you are unable to change the default program extension on Windows 11/10. This is especially frustrating if you are trying to open a program that should have been opening in a different application, let’s say a text file in Notepad, but instead, it opens in a completely different program stripping away the ability to alter the file. In this post, we have given a workaround that allows you to change program extensions using Registry Editor.
Unable to change Default Program Extension in Windows
When I tried to change it back to Outlook under the Properties of that file the change option was grayed out
So I tried right-clicking on the file and clicking on the “Open With” dialog box because there is a change box that says, “Always use the selected program to open this kind of file.”
Strangely, that checkbox was grayed out, as well. When I select Outlook, it opens fine, but I was just unable to set it as the default option.
So I went to Control Panel\All Control Panel Items\Default Programs\Set Associations and tried to change it there, but sadly I was again unable to. I was totally stumped because the UAC was turned off, the user is a Windows administrator – so there was no reason for the option to be disabled.
That’s when I remembered that there is an option in the Windows Registry, where you can change it. So I opened the registry and navigated to the following key:
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts
Here you have to your extension and then go to a key called “UserChoice”.
What this registry key does, is if you change the Default file extension, Windows creates this key and adds the value there.
On the right-hand side you’ll see a string value “Progid” under that value you’ll see the current program that is associated with it. So I tried to change that value but it gave me an error: Cannot edit Progid.
Now I realized what was wrong! For some reason, that specific registry key doesn’t have permission to change the file extension, and that was the reason why those options were grayed out for me. So I took ownership of the parent key and inherited the permission.
Now I could delete the “UserChoice” key. Once I deleted it and I rebooted the system. And voilà – now I got this window!
Once I selected the correct program, I made it as default, and it stayed.
I hope this becomes helpful for someone who runs into a similar problem.
Read: File Association Fixer for Windows
How do I change the default app for extension in Windows 11?
To change the default app for any extension in Windows 11, you can use the Settings app. Then, go to Apps > Default apps. From Set a default for a file type or link type, search for the link you want to configure, click on it, and set its default app.
Read: Remove unwanted programs from Recommended Programs List in the Open With box
How do I reset the default file extension type associations in Windows 11?
To reset all default file extension types in Windows 11, go to Settings > Apps > Default apps. Now, scroll down to reach Related settings, and then click on Reset from Reset all default apps. This will reset the default file extension.
Also Read: How to dissociate File Types in Windows.
