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I have set up a custom file association for .cfg to open in WordPad, but I can't seem to figure out how to remove it. How do I remove file associations in Windows 7?

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marked as duplicate by Peter Mortensen, Tog, Mokubai, Dave M, Breakthrough Sep 8 '13 at 23:12

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5 Answers 5

up vote 9 down vote accepted

From a command window, you can use the "ASSOC" and "FTYPE" commands to add/edit/delete file type associations.

C:>assoc /?  

ASSOC [.ext[=[fileType]]]  

  .ext      Specifies the file extension to associate the file type with  
  fileType  Specifies the file type to associate with the file extension  

Type ASSOC without parameters to display the current file associations.  
If ASSOC is invoked with just a file extension, it displays the current  
file association for that file extension.  Specify nothing for the file  
type and the command will delete the association for the file extension.  


C:>ftype /?  

FTYPE [fileType[=[openCommandString]]]  

  fileType  Specifies the file type to examine or change  
  openCommandString Specifies the open command to use when launching  
  files of this type.  

Type FTYPE without parameters to display the current file types that  
have open command strings defined.  FTYPE is invoked with just a file  
type, it displays the current open command string for that file type.  
Specify nothing for the open command string and the FTYPE command will  
delete the open command string for the file type.  Within an open  
command string %0 or %1 are substituted with the file name being  
launched through the assocation.  %* gets all the parameters and %2  
gets the 1st parameter, %3 the second, etc.  %~n gets all the remaining  
parameters starting with the nth parameter, where n may be between 2 and 9,  

... ...  

So (on my system), regarding .bkr files, these commands return:

C:>assoc .bkr  

C:>ftype bkrfile  
bkrfile="F:\Program Files\path...\program.exe" "%1"  

I created a new "test" file extension/file type (may require admin permissions):

C:>assoc .bzb
File association not found for extension .bzb

C:>assoc .bzb=MyBZBCustomFileType  

C:>assoc .bzb

C:>ftype MyBZBCustomFileType  
File type 'MyBZBCustomFileType' not found or no open command associated with it.  

C:>ftype MyBZBCustomFileType=%SystemRoot%\system32\NOTEPAD.EXE %1  
MyBZBCustomFileType=C:\Windows\system32\NOTEPAD.EXE %1  

C:>echo Some text.>C:\Temp\file.bzb  

C:>start "" C:\Temp\file.bzb  

This opens "Notepad" editing my "dummy" file.

To delete the filetype association, first delete the connection of the filetype to the program like this:

C:>ftype MyBZBCustomFileType  
MyBZBCustomFileType=C:\Windows\system32\NOTEPAD.EXE %1  

C:>ftype MyBZBCustomFileType=  
File type 'MyBZBCustomFileType' not found or no open command associated with it.  

Then delete the file extension association (may require admin permissions):

C:>assoc .bzb  

C:>assoc .bzb=  

C:>assoc .bzb  
File association not found for extension .bzb  

C:>start "" C:\Temp\file.bzb  
(The dialogbox "Windows cannot open this file" opens)  



For a GUI solution, I use PowerTools by Creative Elements. You can download and use it for free for 45 days on trial. This is a collection of tools, and you'd be using their File Type Doctor tool to add/edit/delete file type associations.

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This doesn't seem to work for associations created by the user via the GUI. –  depquid Mar 21 '13 at 18:53
@depquid - Do you get an error message when you try it, or does it just silently fail ? Keep in mind, you may need to open the command prompt as an administrator for it (assoc/ftype) to work. Also, I added info on a GUI (File Type Editor) that I use... it should work for you. –  Kevin Fegan Mar 21 '13 at 19:04
@KevinFegan, Is assoc .bzb= and ftype MyBZBCustomFileType= the official way to delete file associations or is there another proper way to do it? ftype /? and assoc /? doesn't seem to mention using that it's legal to use = to delete file associations. –  Pacerier 2 days ago

You can remove the association in the registry:


and delete the key with the guid that corresponds to wordpad.

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That will remove it altogether if that's what you want. If you just want to change it, right click and choose "Open With". Then choose the new program and check the "always use this to open files of this type". –  LilCodger Mar 21 '13 at 16:14
reg delete HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.cfg –  Steve Pitchers May 1 at 14:32

You can use this cool third-party application, Default Programs Editor:

Default Programs Editor makes it easy to fix file association settings in Windows, including context menu items, icons, and descriptions. Also: autoplay settings and default programs settings ...all without fiddling around in the registry.

Enter image description here

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Right click a .cfg file -> Open with -> Choose Default program. Then check the "Always use the selected program to open this kind of file" and select a program from the list or click the Browse button to manually select a program from the filesystem.

Full guide with images: http://www.sevenforums.com/tutorials/12196-open-change-default-program.html

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Yes, but is it possible to remove it this way? –  Nathan2055 Mar 21 '13 at 21:34

The way to change associations (doesn't seem to let you remove though) this with built-in Windows 7 tools (UI ones) is to open the Start Menu, then choose Default Programs. (Or if it's not present, open Start Menu, Control Panel (might need to change from View by category to View by large icons) and then Default Programs )

Then select Associate a file type or protocol with a program. You'll get a list with the associations currently configured in your computer. Find the extension you want to change and double-click it to change its configuration.

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