Package Manager requires elevation to run, so either start it from an elevated prompt or be prepared to approve the elevation with the UAC prompt.

So to have the command prompt wait for the pkgmgr.exe process to finish before returning, add start /w. The start /w part is necessary because the default behaviour of pkgmgr.exe is to return immediately to the command line even when it is still performing its tasks. Start /w pkgmgr.exe /uu:MicrosoftWindowsPowerShell

Start /w pkgmgr.exe /iu:MicrosoftWindowsPowerShell But as mentioned you can also use Package Manager (pkgmgr.exe) to enable or disable the same features. You can run optionalfeatures.exe to use a GUI to enable or disable the available features. the Remote Server Administration Tools (RSAT) package. When you install the PowerShell package (KB928439) on Windows Vista it extends the list of optional features that can be selected to enable or disable. And it is this last piece of functionality that we are going to be using here. Package Manager can also enable or disable a Windows feature, either offline or on a running Windows installation. Package Manager (Pkgmgr.exe) is a new Windows Vista command-line tool that you can use offline to install, remove, or update Windows packages.

Windows package manager