Restore Default File Type Associations in Windows 10  

Try clearing the root one after exporting the key.. I guess that's what you're planning on.

Otherwise try one of the uninstallers I suggested. Scans may function differently.. or the scan may not pick up the unexpected association 'cos it's not linked in a way the tools can pick up.

I guess it's too late to use a System Restore point to correct the original problem.. expecially as you've probably created a number with the bulk crap tool...

Great news @Cuspate.

mfessler said:

Hello fellow sufferers,

unfortunately, the file associations has become quite confusing in recent years.
Is there a good overview somewhere which registry keys play a role and in which order these are processed?

To test, I gave a file the ending .jjk and then linked it to Notepad with the option "Always use this app...".
Keys or values were created in the following locations:

HKCU\Software\Classes\.jjk\
HKCU\Software\Classes\jjk_auto_file\
HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.jjk\
HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\ApplicationAssociationToasts\ value: "Applications\notepad.exe_.jjk"
HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\ApplicationAssociationToasts\ value: "Applications\jjk_auto_file_.jjkk"

Not used in my example, but is also used in other situations: HKCU\Software\Classes\SystemFileAssociations\
and apart from the third mentioned branch (FileExts), everything is possibly also (or exclusively) set under HKLM.

Does anyone have good reading material on how this works in detail?
If I understand it correctly, built-in tools like ftype, assoc and dism (GPO/DefaultAssociationsConfiguration) (still) cannot handle UserChoice.
So there's nothing left but edit it manually and using SetUserFTA to set it or does anyone have another tip for a good tool that takes everything into account?

Many thanks for any advice!
Regards, Martin

Hello Martin,

When you (current user) set a default app for a file type using "Open with", that user choice is saved to the registry key below.

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\<file type>\UserChoice

ahi said:

Hello,

I accidentally changed the default association for a .sav file and now I can't seem to go back to the original setting. Could you please add .sav to the list?

Thank you for this very helpful thread.
Josh

Hello Josh, and welcome.

The REG file below will clear the user choice you just set to restore the default.

sav.reg

Code:

Windows Registry Editor Version 5.00

[-HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.sav\UserChoice]

ahi said:

Thank you for your quick reply.
I did everything as described in the tutorial, but the extension is still associated to the app I set by mistake.

I merged the .reg file (admin), got a message confirming that "Keys and values were successfully added to the registry", restarted my computer, but nothing changed.
I checked the default app for .sav files, still the wrong one.
I checked the default app for ".reg" files, it is set on Registry Editor, as it should be. Tried merging and restarting again, still not working.
I checked the registry, and there is no "UserChoice" section, only "OpenWithList" and "OpenWithProgids" (I see the undesired app in "OpenWithList)".

Any clue on what could be going wrong here?

Thank you for your help again!

Ok. Let's try the REG file below. It's more thorough.

sav.reg

Code:

Windows Registry Editor Version 5.00

[-HKEY_CLASSES_ROOT\.sav]

[-HKEY_CLASSES_ROOT\SystemFileAssociations\.sav]

[-HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.sav]