Fix All-User Install Agent Errors on Windows 8

We're seeing an increasing trend of the following error displaying on login on our client's computers running Windows 8.  Oddly this seems to be happening more on Windows 8 "Core" (what you receive on a consumer system), versus Windows 8 Pro or Enterprise in the corporate environment. 

Windows couldn't connect to the windows all-user install agent service. Please consult your system administrator.

An investigation points to what appears to be some pretty buggy code in this particular service, which handles the installation of AppX (Metro/Tile World) applications.  Somehow this service is crashing, and then getting set to a Disabled state.

Often, this problem is preventing standard (non-administrator) users from successfully logging on to the computer, or running certain Apps or even desktop applications.

To fix this issue, you must be able to logon as an account that is in the local Administrators group.  Once logged on, to resolve the issue is relatively easy. 

Open a Command Prompt As Administrator (this can be done from the Start Screen by searching for CMD, and then right click on the Command Prompt tile and choose Run as Administrator from the app bar).  Then execute the following three commands:

sc config AllUserInstallAgent start=demand
net start AllUserInstallAgent
sfc /scannow

The first two commands change the startup type of the required problem service, and the third will check for other corrupt file issues in your Windows installation.  It will take a good while to complete. 

The errors should be resolved.  Still no word on an official fix from Microsoft yet.

-Updated June 18, 2013