We see the following event ID is logged in application log:
Log Name: ApplicationSource: Microsoft-Windows-User Profiles ServiceDate: DateEvent ID: 1511Task Category: NoneLevel: WarningKeywords: ClassicUser: UserComputer: ComputerDescription:Windows cannot find the local profile and is logging you on with a temporary profile. Changes you make to this profile will be lost when you log off.
Title: A temporary profile is loaded after you log on to a Windows Vista-based system
Check the following article, which describes about the cause.