When the default user profile is customized in the manner that is described in this article, it reconstructs the source profile in a format that is appropriate for use by multiple users. This is the only supported method of customizing the default user profile for the Windows operating system. If you try to use other methods to customize the default user profile, it may result in extraneous information being included in this new default user profile. Such extraneous information could lead to serious problems with applications and system stability.