Uninstalling applications with GPO that were installed manually or during installation.

I installed applications with MDT during deployment.   I always assumed I could uninstall or update  it easily with a GPO later.  This is not the case. The GPO for software management works for uninstallation but only if it was installed with GPO.

Here's how I removed a few outdated apps.  On a machine with the applications that you want to remove, run:

WMIC product where "name like  '%application name%'" get Name, Version, IdentifyingNumber

The part in bold is the name of your application, run the command for each application.  This will give the product ID.  Use the product ID for a startup script that looks like this:

msiexec /x {XXXX-XXXXX-XXXXX} /qn

The open and close brace are mandatory, this wasn't clear to me in my research.  

Create a GPO in  GPO/computer configuration/Policies/Windows Settings/Scripts (Startup/Shutdown).