Windows 8 or Windows Server 2012-based client computers switch back and forth between the old and new service versions during a Windows Update, Microsoft Update, or Windows Store service migration

This issue occurs because of an issue in the Windows Update Agent software. Therefore, the client computer discards the previously cached configuration files, and uses the newly downloaded configuration files regardless of whether the downloaded configuration files are more recent than the previously cached configuration files.

When a client computer connects to the Windows Update, Microsoft Update, or Windows Store service, the Windows Update Agent software runs on the client computer to receive configuration files that indicate which version of the service the client computer should use. The configuration files are cached locally for later use. During the service migration, the client computer may randomly receive configuration files that refer to either the old version of the service or the new version of the service. This mechanism makes sure that the client computer only uses the newly downloaded configuration files if they are more recent than the previously cached configuration files.

However, because of an issue that occurs in the Windows Update Agent software, the client computer always uses the newly downloaded configuration files, regardless of whether the newly downloaded configuration files are more recent than the cached configuration files. Therefore, the client computer randomly switches back and forth between service versions, depending on which configuration files are most recently received.