How To Fix .Net Framework 4.7.2 Error 643 0x80070643 In Windows Update

By |2018-07-30T15:21:25-05:00July 31st, 2018|Categories: Windows|Tags: , , , , , , , |2 Comments
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While trying to install Microsoft .Net Framework 4.7.2 in Windows Update, you may encounter a fatal error 643 (0x80070643) where the update fails and a server reboot results in the same error. Unfortunately this error dates all the way back to .Net Framework 1.x, so it could happen to any version. You could try the Fix Windows Update Errors Tool from Microsoft, but it probably won’t do much. Microsoft also offers a .Net Framework Repair Tool that you can try.

Try The Offline Installer

The first option to try is to download the full offline installer of the .Net Framework you’re trying to install. As of this article, it is .Net Framwork 4.7.2. If the issue is because of Windows Update, then the offline installer might work. When I ran into this issue, the offline installer worked when Windows Update failed.

Check Registry Files For Permissions

  • Use the Windows key + R to open a run command
  • Type regedit.exe and press OK
  • Navigate to: HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Installer
  • Check if following registry keys have correct values:
    MsiExecCA32 should end with \Windows\syswow64\msiexec.exe
    MsiExecCA64 should end with \Windows\system32\msiexec.exe
  • If those are correct, then highlight one and go to Edit > Permissions and verify that SYSTEM and Administrators have Full Control and not just Read permissions
    Repeat for the other key
  • If you had to make changes to the registry, restart the computer or server and try the installation again

Rebuild Your Windows Update SoftwareDistribution Folder

  • Open a command prompt and type: net stop wuauserv
  • Use the Windows key + R to open a run command and type: %windir% and press Enter
  • In the opened folder, rename the SoftwareDistribution folder to SoftwareDistribution.old
  • Open a command prompt and type: net start wuauserv
  • Try to install .NET Framework again

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  1. Simon Laug October 1, 2018 at 5:06 am - Reply

    I got the same problem. Still having the problem, after i tryed your methode windows installed .Net 4.7.2 and at 100% it stoped and showed me an error message, the same as you got. Still looking for an working workaround. It seems the probleme is still a bigger issue than moste of us think. I even tryed to unistall previews version of .net which didn’t work as well.

    I Hope i will soon finde a workaround cause this problem is bondet to 5-7 Servers in our Network.

  2. fln March 13, 2019 at 11:22 am - Reply

    I was suffering the same problems. I had to reinstall windows itself due to problems with user control system. Result: Some installations were corrupted – including the .Net-Framework.
    Reinstallation would not work with the windows update nor going through your steps. registry keys were fine and reseting that folder had no impact.

    What just helped for me – thank god – was to download the manual .Net-Installer and to first remove 4.7.2 installation and then to reinstall it.

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