How to Configure Default File Associations in Windows 11/10

In this article, we will look at the main ways to manage File Type Associations (FTA) with default apps in Windows from a system administrator’s perspective. A file association in Windows defines the relationship between a file type (extension) and the program used to open it by default. Note that some methods of managing file associations that worked in previous Windows versions either no longer work or work only partially in modern versions of Windows 10/11 and Windows Server 2022/2025.

As an example, we will show how to configure the default app for opening *.pdf files in Windows manually, through the command line, by exporting the current file associations from a reference computer to an XML file and applying that file to other computers manually or through Group Policy. We will also cover the specifics of configuring user-level and system-level file associations in the current Windows 11 25H2 build.

How to Set a Default Program for a Certain File Type in Windows 11

First, let’s look at the official administrative method for exporting and importing file association settings. This method works in both Windows 10 and Windows 11; it is not blocked by Windows 11’s built-in User Choice Protection mechanism and is not automatically reset by the system.

Suppose you want to set Adobe Acrobat Reader DC as the default app for opening *.PDF files on all computers in the domain. In other words, you want to associate the .pdf file extension with a specific program. To do this, we need a reference Windows computer with Acrobat Reader installed (in this example, the computer running the current Windows 11 25H2 build).

To manually create an association between a file extension and a program:

1. Go to Settings -> Default Apps (or run the Settings URI command -> ms-settings:defaultapps ).
2. In the Set a default for a file type search bar, type the file extension .pdf.
3. The program currently assigned to this file type will appear below the search bar (by default, Windows 11 opens PDF files using the Microsoft Edge browser)
4. Click on the assigned app and select Adobe Acrobat from the list of registered apps. If it doesn’t appear in the list of recommended apps for some reason, specify the path to the executable file manually. For example: "C:\Program Files\Adobe\Acrobat DC\Acrobat\Acrobat.exe"
5. Click the “Set as default” button

You can automatically assign a specific app to the file extension for which it is registered. To do this, find your program in the Default Apps section and click on it.

A list of file types supported by this app will appear on the screen that opens. Choose which file extensions you want to open by default using Acrobat Reader.

Export and Import Default App Associations on Windows to the XML file

Once you have configured the necessary file-to-program associations for a user on a reference computer, you can export the current settings to an XML file using the DISM command:

Dism.exe /online /Export-DefaultAppAssociations:C:\PS\DefaultAssoc.xml

You can open the DefaultAssoc.xml file with any text editor and see the full list of file associations exported. If you need to use only some of the file associations from this list (in order not to override the existing user associations), you can manually edit the XML file. Only keep the lines containing the file extensions that you need. For example, we’ll leave the following lines for PDF and FDF extensions:

<?xml version="1.0" encoding="UTF-8"?>
<DefaultAssociations>
<Association Identifier=".fdf" ProgId="AcroExch.FDFDoc" ApplicationName="Adobe Acrobat Reader DC" />
<Association Identifier=".pdf" ProgId="AcroExch.Document.DC" ApplicationName="Adobe Acrobat Reader DC" />
</DefaultAssociations>

The resulting XML file can be imported into other computers using the DISM command:

Dism.exe /Online /Import-DefaultAppAssociations:C:\PS\DefaultAssoc.xml

You can also import file association settings to an offline Windows image in a WIM file (that is used to deploy your custom Windows image to new computers).  First, mount the image:

Dism /Mount-Image /ImageFile:C:\mnt\images\install.wim /MountDir:C:\mnt\offline

Then import the XML file:

Dism.exe /Image:C:\mnt\offline /Import-DefaultAppAssociations:\\Server1\Share\DefaultAssoc.xml

Configure Default File Associations via Group Policy

A special Group Policy option is available in Windows 10/11 and Windows Server 2025/2022/2019/2016 that allows an XML file containing file association settings to be applied to all current users of the computer.

For example, you want to apply a Group Policy with file association settings to all the computers in a specific OU (Organizational Unit) of Active Directory.

1. Open the Group Policy Management console.gpmc.msc ).
2. Find the OU containing the computers to which you want to apply file associations and create a new GPO.
3. Edit the new GPO and navigate to Computer Configuration -> Administrative Templates -> Windows Components -> File Explorer.
4. Find the option Set a default associations configuration file;
5. Enable the policy and specify the UNC path to your XML file (make sure the path doesn’t contain quotes or spaces). It can be located in a shared network folder, SYSVOL directory on the domain controller, or pre-copied to the computers using GPO or SCCM. 
6. Restart your computer to apply the new file associations.
   You can use the gpresult.exe tool to troubleshoot GPO problems.

The new file association settings will be applied to all users of the computer the next time they sign in.

The path to the XML file with the new file association settings is contained in the DefaultAssociationsConfiguration registry parameter under the key HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\System.

This policy applies to all users at the computer level (machine-level). It cannot be scoped to specific users or groups. The new file association settings are applied when the user signs in. Although the user can change the assigned file associations during their session, they will be overwritten by the settings from the XML file the next time the Group Policy settings are updated.

Because Windows 10 and 11 track changes to file associations, the first time a user attempts to open a PDF file, Windows may display a confirmation dialog asking whether Acrobat Reader should be used as the default application for this file type. This prompt is displayed only once.

A similar notification is also displayed after installing a new application that is registered to open an existing file type or protocol. You can suppress these notifications by enabling the Do not show the ‘new application installed’ notification policy in the same GPO section.

How to Set File Associations from Command Prompt

In earlier versions of Windows, the built-in command ASSOC could be used to set file type associations with apps.  For example, to check the program that should be used to open PDF files, run the command:

assoc .pdf

In this example, you can see that the AcroExch.Document.DC file type is associated with the PDF file extension:

.pdf=AcroExch.Document.DC

The assoc command returns the app aliases. To understand which binary the AcroExch.Document.DC app is associated with, run:

ftype AcroExch.Document.DC

You can set the type for a specific file type with the command:

ASSOC .csv=txtfile

In this example, we have specified that all CSV files should be opened as plain text files (using notepad.exe by default).

You can create or change the association of a file extension with a program from the command prompt. For example, you want all files with the .tx1 extension to open with notepad++.exe. First, you need to associate the .tx1 extension with the new tx1file file type.

assoc .tx1=tx1file

Now, set the app to open files with the .tx1 extension by default.

ftype tx1file="%programfiles(x86)%\"Notepad++\notepad++.exe" "%1"

However, in Windows 11, system protection will reset any changes to the file associations made using the command below:

assoc .pdf=MSEdgePDF
ftype MSEdgePDF="C:\Program Files(x86)\Microsoft\Edge\Application\msedge.exe" -- "%1"

Registry Location for File Extension Associations

The file association settings are stored in the Windows registry. In the previous section, we showed how to configure the .PDF file type association with Acrobat Reader using an XML file and Group Policy. Now let’s see how it looks in the Windows Registry.

Run the Registry Editor (regedit.exe) and go to the registry key HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\ Explorer\FileExts\.pdf\UserChoice. This registry key contains the association settings for the PDF file extension.

Please note the following registry parameters:

• ProgId – this is the text identifier of the registered app to open this file type. This app ID is specified in the XML file. If a long identifier is specified instead of the application name, then the file association with the Microsoft Store (UWP) app is configured.
• Hash – a hash value that is automatically generated to validate the file association with the program (it is calculated based on the user’s SID, the file extension, the ProgID value, and the system key). The presence of this hash confirms that this file association was configured manually by the user or administrator via GPO. This security mechanism is designed to protect users from malware that can change file associations without the user’s approval.

If you try to manually change the ProgId registry value and assign another program, the Hash value will no longer be valid. In this case, Windows will automatically reset the file association settings to the default state, and the user will receive a notification:

An app default was reset.
An app caused a problem with the default app setting for .html files, so it was reset to Microsoft Edge.

Accordingly, in Windows 10 and 11, you won’t be able to configure file associations through the registry, as you could in Windows 7. In addition to ACLs, the values ​​in this registry key in Windows 11 are protected by a special UCPD driver.

User Choice Protection Driver: Prevent File Association Changes in Windows 11

In 2024, a special kernel-level driver known as the User Choice Protection Driver (UCPD) was added to Windows 10 and 11. It is designed to prevent direct modifications to the registry keys that are responsible for default file and protocol associations. In particular, this protection applies to the HTTP and HTTPS protocols and to PDF files.

For example, if you try to manually change a value under the following registry key, an error will appear: HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.pdf\UserChoice

Protected file associations can only be changed manually via the Settings app or via Group Policy.

The UCPD driver’s task is to prevent third parties from changing the associations of certain file types without the user’s knowledge. It is also intended to prevent a ‘browser default’ battle when several alternative browsers are installed on the device.

Change Default File Associations in Windows 11 Using SetUserFTA

To programmatically change a user’s file associations in Windows, you can use the third-party console command SetUserFTA (https://setuserfta.com). This utility allows you to write the assigned ProgID value for a file extension directly to the registry and immediately updates the hash value.

To list the current file associations and the ProgID set for them in Windows, run this:

SetUserFTA get

To set an association for a specific file extension, use the command:

SetUserFTA.exe extension progid

You can find the ProgID assigned to a program using the following command:

SetUserFTA.exe get | findstr /I "pdf"

To set PaintDotNet++ as the default app for opening BMP image files, for example, run the following:

SetUserFTA .bmp paintdotnet

Or set the default application for PDF files:

SetUserFTA.exe .pdf Acrobat.Document.DC

The utility updated the ProgID value correctly and recalculated the hash sum for this file type in the registry.

For example, set Chrome as the default browser for HTTP/HTTPS protocols and HTML files:

SetUserFTA .http ChromeHTML
SetUserFTA .https ChromeHTML
SetUserFTA .htm ChromeHTML
SetUserFTA .html ChromeHTML

If the application doesn’t have a registered file class or ProgID, you can specify its executable. For example:

SetUserFTA .txt applications\notepad++.exe

The SetUserFTA tool supports using the configuration files. You can set multiple file associations at once by creating a text file named userfta.cfg in the following format:

.pdf, Acrobat.Document.DC
.bmp, paintdotnet
.txt, applications\notepad++.exe

To apply the file associations from the config file in bulk, run:

.\SetUserFTA.exe .\userfta.cfg

A notification about using the free version appears every 10th time the SetUserFTA tool is launched. The launch counter is stored in the RunCount parameter within the HKEY_CURRENT_USER\Software\Kolbicz IT\SetUserFTA registry key. To prevent these notifications from appearing, lock the current value of the parameter (using Windows Event Triggers with an assigned Task Scheduler job or Group Policy Preferences).

How to Reset File Associations to Default in Windows

Use the following command to reset any previously imported file association settings on a Windows computer:

Dism.exe /Online /Remove-DefaultAppAssociations

After running this command, all new users will be logged in with the default file association settings (the reset has no effect on the existing user profiles).

In order to reset the file associations configured manually by the user to the default ones, you need to click on the Reset button in Settings -> Apps -> Default Apps.

This will restore all file associations to their original state, as they would be in a clean Windows 11 installation.