What is WMSysPr9.prx, Is it Virus or Safe?

  • Ankita 
  • OS

It is a Windows system file and WMSysPr9.prx should not be removed.  Most people are unaware of the function of this file and hence might wonder what it is? I have provided detailed information about this file below.

What is WMSysPr9.prx?

It is an inbuilt Windows system file that is used for the dial-up modem or ISDN connection. If you open the WMSysPr9.prx file using notepad then you will file the below description:

“Use this multiple bit rate profile for target audiences with a dial-up modem or single-channel ISDN connection (bandwidth is between 28.8 Kbps and 56 Kbps”

This file belongs to the package of the Windows Media Format SDK and is a collection of system profiles. System profiles include ASF files. Thus, we can say that WMSysPr9.prx stores the profile information on disk in the form of an XML file having .prx file name extension.

You may use software like DU Meter to monitor data transfer on your system.

File Size & Location

By default, WMSysPr9.prx is located under C:\Windows\ directory and the average file size is about 309 KB.  But more than one copy of the file can be found under C:\Windows\WinSxS\ folder. Here is a quick overview WMSysPr9 file:

ParametersFile Information
SoftwareWindows Operating System
File LocationC:\Windows\WinSxS
TypePRX File
File Size309 KB

Is it a virus? How to remove it?

Sometimes, a Trojan with this name is also picked up by some antivirus programs. The Trojan can grant remote desktop access to hackers who can hack into your system to gain personal data. Otherwise, it may help download other malware and impact the system performance terribly.

Thus, it is recommended to get rid of this Trojan immediately.

For this purpose, you could either employ a trusted and efficient antivirus solution to remove the Trojan from your PC. Otherwise, you could manually remove it too in the following ways:

  • From the Task Manager, terminate all the processes associated with WMSysPr9.prx.
  • Remove the registry entries from the Registry Editor linked with the WMSysPr9.prx.
  • Delete the files of WMSysPr9.prx from the system.

For the safer side, it is recommended to take registry backup before you make any changes in the registry.


In short, WMSysPr9.prx file is not malware or a virus, instead, it is a system file and it should not be removed from the system. If you have any doubts or queries, then feel free to drop them in the comments box below, and I will get back to you with answers.



Founder and Writer @ WinOSBite. Future plan is to make this platform open to community to resolve and discuss various issues, usage related to Operating System.

Leave a Reply

Your email address will not be published. Required fields are marked *