I see this when using Robocopy.exe version XP027 and trying to copy inherited permissions. In the XP026 and earlier versions inherited permissions from the source would be copied to the destination. This is no longer the case in XP027. Why Does this Happen
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Read the complete post at http://blogs.technet.com/ben_parker/archive/2009/07/01/the-security-permissions-aren-t-the-same-when-i-use-robocopy-copyall-or-robocopy-sec.aspx