Windows 7 SP1 installation fails with error 0x800f0818

I came across a peculiar problem today trying to install SP1 on a Windows 7 laptop. Whenever I ran the Windows 7 SP1 installer or tried to update to SP1 using Windows Update the installation failed with a cryptic error ‘0x800f0818‘. I tried various things such as running sfc /scannow and installing the Windows 7 System Readiness Tool (64 bit in my case), but neither reported problems.

After a bit of digging I found an entry in the CheckSUR log file found in C:\Windows\Logs\CBS which seemed to be related. In this case a .Net Framework update had failed to install a few times and this particular update was referenced in the log file:

Checking Windows Servicing Packages

Checking Package Manifests and Catalogs (f) CBS MUM Corrupt 0x00000000 servicing\Packages\Package_for_KB979916_RTM~31bf3856ad364e35~amd64~~  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: 485  Found 1 errors   CBS MUM Corrupt Total count: 1

Unavailable repair files:  servicing\packages\Package_for_KB979916_RTM~31bf3856ad364e35~amd64~~  servicing\packages\

To fix the problem I had to remove entries for the corrupt package from the registry (IMPORTANT: taking a backup first) from:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Component Based Servicing\Packages

The specific entries are shown below. There are two, the highlighted entry, and the one beneath:

Deleting corrupt package entries from the registry


After deleting the two entries I reran Windows Update checking for updates and this package was redownloaded and then installed without issue. After this the service pack 1 installation proceeded without error. You may find that the specific update referenced in your CheckSUR log is different to the one mentioned here, but the method is the same.


5 Responses to Windows 7 SP1 installation fails with error 0x800f0818

  1. Jack Cole says:

    I get “Cannot Delete *registry name*: Error while deleting key.”

    I have the same problem as you, but this error is what’s preventing me from progressing.

    (f) CBS MUM Corrupt 0x800F0900 servicing\Packages\Package_for_KB2658846_SP1~31bf3856ad364e35~amd64~~ Line 1:
    (f) CBS Catalog Corrupt 0x800B0100 servicing\Packages\
    (f) CBS MUM Corrupt 0x800F0900 servicing\Packages\Package_for_KB2658846~31bf3856ad364e35~amd64~~ Line 1:
    (f) CBS Catalog Corrupt 0x800B0100 servicing\Packages\

    • oasysadmin says:

      Check the permissions on the registry key. You may need to assign yourself the rights to delete the key, in fact I seem to remember having to do this myself.

    • Jack Cole says:

      Found the issue: It’s related to permissions.

      Right click the registry entry, then select permissions. Click Advanced, then select the owner tab, check “replace owner on subcontainer and objects”, then select Administrators and hit OK

      Then click your name on the list, check the box under “allow” for Full Control and hit OK. You can now delete it.

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