Cannot associate .PDF with anything other than Microsoft Edge

When you use Default Apps or Open With to associate .PDF files with Adobe Reader or any other app, nothing may happen. In some cases, the association will change for a brief time, and then it will revert to Microsoft Edge as the default.

Possible Cause

In recent builds of Windows 10 and 11, the .PDF association registry key (i.e., “.PDF\UserChoice“) registry key is protected by the User Choice Protection Driver (UCPD.sys).

However, the UCPD driver is not supposed to stop you from changing the file associations via Open With or Default Apps. It’s unknown why the association change is blocked.


Disable the UCPD driver and its scheduled task. To do so, run these commands from an admin Command Prompt:

sc.exe config UCPD start= disabled

schtasks.exe /change /Disable /TN "\Microsoft\Windows\AppxDeploymentClient\UCPD velocity"

Restart Windows.

Open Task Manager and end all instances of msedge.exe.

Alternatively, you can run the following command to kill all msedge.exe instances.

taskkill /im msedge.exe /f

taskkill all instances of microsoft edge msedge.exe

Now, see if you can change PDF associations via Default Apps or Open With.

(Windows 11 23H2 and Microsoft Edge v124.0.2478.80.)

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Ramesh Srinivasan is passionate about Microsoft technologies and he has been a consecutive ten-time recipient of the Microsoft Most Valuable Professional award in the Windows Shell/Desktop Experience category, from 2003 to 2012. He loves to troubleshoot and write about Windows. Ramesh founded in 2005.

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