Troubleshooting a Failed Microsoft Security Essentials Install – Error Code 0x80070643


I was working on my daughter’s Windows 7 computer last weekend and one of the first things I noticed was she hadn’t installed any updates for quite a while. It took a couple of update cycles to get her machine current.  Once it was, I noticed the antivirus software the computer had come with had expired.  I uninstalled the expired antivirus software and downloaded the free Microsoft Security Essentials.  It should have been a simple task to install the new antivirus software, but it wasn’t.  Within 5 minutes or so it failed to install with an Error Code 0x80070643.

I found this on and followed the suggestions.  It said to look in the c:\ProgramData\Microsoft\Microsoft Security Essentials\Support\msseInstall.log installation logfile and search for the string “return value 3”.  This system didn’t have that path or logfile.  Apparently this has changed in the latest version of Security Essentials.  The new file location and file is C:\ProgramData\Microsoft\Microsoft Security Client\Support\MSSecurityClient_Setup_mp_ambits_Install.log.

I did a search as suggested and found the following in MSSecurityClient_Setup_mp_ambits_Install.log:

MSI (s) (64:38) [13:17:21:123]: Product: Microsoft Antimalware -- Error 1606. Could not access network location %APPDATA%\.

MSI (s) (64:38) [13:17:21:123]: Note: 1: 1606 2: %APPDATA%\
MSI (s) (64:38) [13:17:21:123]: Product: Microsoft Antimalware -- Error 1606. Could not access network location %APPDATA%\.

Action ended 13:17:21: CostFinalize. Return value 3.

A quick search of Error 1606 got me to this Microsoft Support article.  It says the problem is caused by an “…an incorrect setting in one of the following registry subkeys:

  • HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\User Shell Folders

  • HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Explorer\User Shell Folders “

In the resolution section it has a link to MicrosoftFixit50356.msi which automatically fixes the registry subkeys.  It also includes a detailed description of how to do it manually, but I opt for the simple route.  Run the .msi and then retry the install.

Security Essentials now installs with no problems.  Once installed, and just to be on the safe side, I start a Full Scan.  I know this will take a while, so we leave this running to go out to lunch.

Comments (2)

  1. Burritos at Barberitos in Athens, GA  –

  2. Kevin Remde says:

    But what I want to know is… What did you have for lunch?

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