System hacks: completely cancel the file and the program associated with the method more

Usually, when we double-click a file, we can automatically run or open the associated program, which is a good thing, but sometimes when we mistakenly associate a “useless” file type with a program, double-clicking the file will call out an unrelated program and try to open the file, which of course we don’t want. It’s easy to re-establish the association of a file with a program, but what can we do to remove this unwanted association completely?

1. Verify and cancel the association with a command

Click on the Start button and type “CMD”, then select “Run as administrator”. In the Command Prompt (Administrator) window, it is best to first check the file extension association with the command “assoc .extension” (replace .extension with the extension you want to check when using it). After confirming that you want to unassociate the file with this extension, execute the command “assoc .extension=” (again, replace the .extension extension with the actual one) (Figure 1). 2.


2. Using fake file type associations to “obfuscate”

This is a bit of an odd idea, but it does work. The way to do it is to find a random EXE program, make a copy of it, first associate the extension you want to handle with the copy, and then delete the copy. This way, since the open program is gone, double-clicking on the file with that extension will naturally prevent it from opening again.

3. Unassociate file types from the registry

First open the Registry Editor and locate “HKEY_CLASSES_ROOT\”. Then find the extension branch to deal with, double-click the “Default” name in the right pane, and clear the “Value Data” value in the pop-up window, OK (Figure 2).


4. Use a variety of third-party software to solve

If you think the above method is complicated, you can also use third-party software to deal with it. There are many third-party software available. If you are still using Windows 7, you can use Unassoc, a software designed for that system (download at It is very easy to use, just select the file extension in the list and click on “Delete file type” to delete the association.

The program is a portable program that can be used without installation after unzipping and is only 100KB in size. Unfortunately, it only works on Windows 7 and does not support Windows 8 or Windows 10.

However, we found another software FileTypesMan suitable for use in Windows 8 or Windows 10 (FileTypesMan is divided into x86 and x64 versions, which can be downloaded as needed. x64 version is available for download at, and the x32 version can be downloaded at the above address minus the “-x64”). This software is also portable. After starting the software, find the extension you want to work with in the list of windows, and then you will see the programs associated with that extension in the window below. To delete the program associated with that extension, simply click on the Edit menu and select the “Delete Selected Extensions” option from it. We can also delete the extension by pressing the Ctrl+Del key combination after selecting it directly (Figure 3).


In addition, we can also use the “Default Programs Editor” software to unlink programs (download at Although this software is an older version of 2010, it still works on Windows 10 and requires the installation of .

After the program is running, first select “File Type Settings” from the main menu (Figure 4); then in the bottom right corner of the pop-up window, select “Delete an Extension” (Figure 5). Finally, select the program extension you want to delete from the list, and click the “Delete Extension” button to unlink it (Figure 6).




Click on the drop-down list after the Delete button and you will see an option to save the operation to a .REG file. If you want to remove some common file associations, you can consider saving a .REG file and just click on it on another Windows computer to quickly remove the association between that extension and the program, without using any other tools.

Alternatively, we can use a simple file type editor called Types (download at: When installing this software, you can choose to add the program options to the control panel, right-click menu, etc., as needed (Figure 7).


To unlink a file extension from a program, simply start Types, find the file extension in the window and click on it, then click on the cogwheel “Properties” button (or double-click on the class) and under the Class tab, uncheck “Use linked class under the Class tab and uncheck “Use linked class” (Figure 8).


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