Windows Vista – Remove File Associations And Unassociate File Types Using Simple Commands

Windows Vista allows you to edit, change or set file associations for various file extensions/ types and protocols using a Graphical User Interface (GUI) so that the files open with the respective associated default programs. However, Vista possesses no tool to unassociate file extensions and remove already existing file type associations from the registry.

Nevertheless, there are two command line utilities in Windows Vista using which you are able to remove all the file type associations. Follow the below mentioned process to make use of the commands “assoc” and “ftype” in order to unassociate default programs associated to a file extensions.

The process is illustrated with an example for removing the extension “.rar” associated with “winrar.exe”:

  1. Open the command prompt with administrator rights.
  2. Type in the below mentioned command to remove file association related to a file extension and press “Enter” Key:

    assoc .ext=

    ext” needs to be replaced by the actual extension that you wish to unassociate. You need to replace “ext” with “rar” in this case, i.e. “assoc .rar =”
  3. Once you dissociate a file extension from a default program, that program won’t be shown within “Open With” list options for that particular file extension.
  4. Now run the below mentioned command to delete or remove the default program associated with the open command for launching files of a particular file type and press “Enter” key:

    ftype FileType

    FileType” needs to be replaced by the actual file type related to the extension which needs to be removed. In this case, you need to replace “FileType” with “WinRAR”, i.e. “WinRAR=

  5. In case you are unsure of the correct file type, you need to just type “ftype”, which will list all file types that are defined into the system or type “assoc”, which will show the associated file type after the extension.

Now that you have unassociated the file association related to a particular file extension, whenever you double-click on a file with that extension, you will be prompted with a dialog box saying that there is no program associated with the file type for performing the selected action and you need to create one using the “Set Associations” option from the Control Panel.

However, you may right-click on that file and use the option “Open with” from the context menu to select an appropriate program to open it and also set the proper file type association.


  1. Thanks for all your helpful information. With XP you can easily associate and unassociate file types to a program or application, from the Control Panel or by selecting: Tools \ Folder Options on the menu of a folder.With Vista, for some unknown reason, you can only associate file types, but you can not unassociate (delete) a file type completely. The only option allowed is to associate the file to another program or application. .Visit to get more information on this topic.