In order for the Background Update Agent to work, it needs to be able to access the update directory. This is a problem in the current configuration, because the update directory is in a user's home directory. Not only does the Background Update Agent not know which user's home directory to look in, but it may not have permissions to access any a user's home directory.
An additional benefit of this change should be that if an update download is in progress, and then the user logs out and another user logs in, the new user should be able to resume the download started by the old user.
It seems that the proper location for this directory in Windows is the %ProgramData% directory, which is intended for storing non-user-specific application data.
