How to: Uninstall Microsoft Security Essentials on Windows Server 2012 R2

With past version of Windows Server, we were provided with Microsoft’s own Security Essentials anti-virus as a free anti-virus solution. This was great for organisations where the budget or other reasons simply do not allow for a paid AV solution. Unfortunately, however, it is no longer supported in Windows Server 2012 R2 and Microsoft have not provided us with an alternative until Windows Server 2016 (Windows Defender).

Many of us worked around this by installing MSE using the unsupported method of enabling compatibility mode and installing using the /disableoslimit switch. Again, however, this means we cannot remove it using the normal method (Add/Remove Programs).

Again, thanks Microsoft!

Well, fortunately, we can also trick Windows into allowing us to remove MSE.

Step one – run in compatibility mode:

Go ahead and locate the setup executable located in the following path:

C:\Program Files\Microsoft Security Client\Setup.exe

Set the compatibility settings on this file by right clicking the file and clicking “Properties. Underneath the “Compatibility” tab, and tick “Run this program in compatibility mode for:” and pick Windows 7 from the dropdown. Click OK to continue.

(Ignore the file name of the properties dialogue above – this screenshot is from the original installation – yours should be for setup.exe)

Step two – uninstall the application using command prompt:

Woohoo! You’re now ready to remove MSE. Not so fast, however!
We must uninstall the application using command prompt, as we must pass it a switch telling it to disable the OS limitation and a switch to initiate the installer in “uninstall” mode. Go ahead and run command prompt as administrator, and then execute the following commands:

cd “C:\Program Files\Microsoft Security Client”
Setup.exe /disableoslimit /u

This should now launch an uninstallation which will succeed and allow you to proceed all the way through.

You have now successfully removed MSE!