Sometimes I have experienced an error when trying to uninstall MPOS or any other program for that matter.

MPOS uninstall

Corrupted registry keys are one of the reasons for such an error.

The following utility from Microsoft helps to cleanly uninstall MPOS  or any other program not uninstalling in such a situation.

https://support.microsoft.com/en-gb/help/17588/fix-problems-that-block-programs-from-being-installed-or-removed

In addition you may also needed to follow these steps to make sure all MPOS packages are removed (especially when multiple user profiles are setup)

  1. Run the following powershell script as Admin user. (Note that you can run the Powershell command by loading it the command prompt by executing powershell command as shown below)

Get-AppxPackage *pos* – allusers

Uninstall

2.  Note the PackageUserInformation in the above results. It will list the users for which the package has been provisioned. The package can then be removed using the following script.

Get-AppxPackage *pos*  | Remove-AppxPackage

Note – You will need to execute the above command for each user by logging in as that particular user in command prompt. For instance lets consider that there are two users admin and user1. You will need to execute the powershell twice, once as admin and once as user1, by using “Run as a different user” option by right clicking the command prompt icon

Run as a different user menu

Hope this helps

-Hitesh Manglani