Error during SP1 Installation

Let's starting this article informing of course the SP1 will help you and don't be afraid.
So, I'm talking about the SP1 but one specific error that I saw and could fix it.

If you're getting the following message error maybe the way to find the root cause will be the same.
You cannot install the SP1 and error message is 0x800F0818


Install Windows Server Service Pack .
Installation was not successful
An unknown error has occurred
Error: 0x800F0818
Solution
========
  
    • First let's go under "C:\Windows\Logs" folder and find the file CheckSUR.log
    • Opening it we can see the following or too similar message:
   
    =================================
    Checking System Update Readiness.
    Binary Version 6.1.7601.21645
    Package Version 11.0
    2011-03-25 20:17
   
    Checking Windows Servicing Packages
   
    Checking Package Manifests and Catalogs
    (f)    CBS MUM Corrupt    0x00000000    servicing\Packages\Package_for_KB2467023_RTM~31bf3856ad364e35~amd64~~6.1.1.1.mum        Expected file name Microsoft-Windows-Foundation-Package~31bf3856ad364e35~amd64~~6.1.7600.16385.mum does not match the actual file name
   
    Checking Package Watchlist
    Checking Component Watchlist
    Checking Packages
    Checking Component Store
   
    Summary:
    Seconds executed: 184
     Found 1 errors
      CBS MUM Corrupt Total count: 1
   
    Unavailable repair files:
        servicing\packages\Package_for_KB2467023_RTM~31bf3856ad364e35~amd64~~6.1.1.1.mum
        servicing\packages\Package_for_KB2467023_RTM~31bf3856ad364e35~amd64~~6.1.1.1.cat
   
    • Download the HF 2467023. Extracted the HF under C:\HF2467023 folder.
   
    • We cannot delete or copy any file to folder "C:\Windows\servicing\Packages".
    • Read this article that explained how to change the permission http://blogs.technet.com/b/roplatforms/archive/2010/05/12/how-to-fix-server-manager-errors-after-installing-updates-hresult-0x800f0818-hresult-0x800b0100.aspx
   
    This makes the current logged on user (needs to have Administrative privileges) owner of that folder:
    takeown /F c:\Windows\Servicing\Packages /D y /R
   
    Then assign full control using:
    cacls c:\Windows\Servicing\Packages /E /T /C /G "UserName":F
   
    • Deleted the files
        C:\Windows\servicing\packages\Package_for_KB2467023_RTM~31bf3856ad364e35~amd64~~6.1.1.1.mum
        C:\Windows\servicing\packages\Package_for_KB2467023_RTM~31bf3856ad364e35~amd64~~6.1.1.1.cat       
    • Copy the file from Extract Folder C:\HF2467023 to C:\Windows\servicing\packages folder.
    Package_for_KB2467023_RTM~31bf3856ad364e35~amd64~~6.1.1.1.mum
    Package_for_KB2467023_RTM~31bf3856ad364e35~amd64~~6.1.1.1.cat
   
    • After completing this action we could start the installation of SP1.
    •  You can see other KB on the CheckSUR.log but the way to fix is the same.
Articles Related
===============
http://support.microsoft.com/kb/947821
http://blogs.technet.com/b/roplatforms/archive/2010/05/12/how-to-fix-server-manager-errors-after-installing-updates-hresult-0x800f0818-hresult-0x800b0100.aspx