This may occur when the membership of the local Users group is changed from the default settings. By default, the local Users group should contain the Interactive account and the Authenticated Users group.
By default, User Account Control (UAC) is enabled. At logon, the standard user access token is built, and if the Users group is missing the default members, the user will be unable to interact with the desktop, resulting in the blank desktop being displayed.
Hope this resolves your Query !!
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