MSE v2.0.657.0 (latest) install error 0x80070643


I am having tremendous issues installing the latest version of MSE. The error dialog I am getting during the installation can be observed on the following image:

enter image description here

OS: Windows XP Home Edition SP3 with all of the latest updates.

I have practically performed every step mentioned in various tutorials on solving the issue, however, with no avail.

I get this when installing Windows Update Agent ("WindowsUpdateAgent30-x86.exe"):

enter image description here

I already have the latest v. of Windows Installer:

enter image description here

Please, find the install error logs here (all in one file):



Another thing to note is that, somehow, when launching MRT – nothing happens, I don't get any visible window or anything and Windows Update always tries to offer the same version of MRT over and over (and seems to succeed in installation, but with another check it offers the same v. again).

Would be of great help if someone could assist me.

asked on Super User Sep 19, 2011 by electroglow • edited Sep 19, 2011 by slhck

1 Answer

  1. You have other Security Software Installed that needs to be uninstalled first.

  2. Windows One Care was installed and removed, but needs cleaned up prior to MSE Install using a One Care cleanup tool.

  3. You need Windows installer 3.1 or above to be installed first

If the workarounds above do not resolve your issue, check the install logs:

1.Find the install logs from this path: (XP)

\Documents and Settings\All Users\Application Data\Microsoft\Microsoft Security Essentials\Support\msseInstall.log


\ProgramData\Microsoft\Microsoft Security Essentials\Support\msseInstall.log

2.Open the log and search for "return value 3" and you will see the error just above the first result. See sample logs below. If you see the same items within the log, continue to the next step.

MSI (s) (CC:2C) [13:27:24:987]: Hello, I'm your 32bit Elevated custom action server.

MSI (s) (CC:E0) [13:27:25:283]: User policy value 'DisableRollback' is 0

MSI (s) (CC:E0) [13:27:25:283]: Machine policy value 'DisableRollback' is 0 Action ended 13:27:25: InstallFinalize. Return value 3.

3.Click Start then click Run

4.Give everyone permission to the desktop by typing the following command:

     >CACLS “c:\documents and settings\all users\desktop” /t /g everyone:f

5.Give everyone permission to the Program menu by typing the following command: ·


CACLS “C:\ProgramData\Microsoft\Windows\Start Menu\Programs” /t /g everyone:f .


CACLS “C:\Documents and Settings\All Users\Start Menu\Programs” /t /g everyone:f

Source Of Information and more details

answered on Super User Sep 20, 2011 by Moab

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