**added error code to title**
original title: I cannot remove or repair .NET Framework 4 because: Fatal error during installation. What should I do?
Windows Update can't install the latest update for .NET Framework 4; it's tried automatically many times and failed, and when I try to update it manually it hangs up and does nothing.
Troubleshooting led me to a problem with corrupted files on my machine, with the solution being to repair Microsoft .NET Framework 4 via "Programs and Features' (Windows 7 Professional edition, 64-bit).
When I try to repair or remove Microsoft .NET Framework 4, either process fails after only a moment. The result is a message saying that the repair or removal did not succeed because: Fatal error during installation.
I've rebooted and shut down all applications except Norton 360 and tried again, but I can't remove or repair the .NET Framework 4.
The log of the error reads thusly:
OS Version = 6.1.7601, Platform 2, Service Pack 1
OS Description = Windows 7 - x64 Service Pack 1
CommandLine = "C:\Windows\Microsoft.NET\Framework64\v4.0.30319\SetupCache\Client\Setup.exe" /repair /x86 /x64 /parameterfolder Client
TimeZone = Central Daylight Time
Initial LCID = 1033
Using Simultaneous Download and Install mechanism
Package Name = Microsoft .NET Framework 4 Client Profile Setup
Package Version = 4.0.30319
User Experience Data Collection Policy: Disabled
Operation updated to: Uninstalling
ServiceControl operation succeeded!
MSI (C:\Windows\Microsoft.NET\Framework64\v4.0.30319\SetupCache\Client\netfx_Core_x64.msi) Uninstall failed. Msi Log: Microsoft .NET Framework 4 Client Profile Setup_20120427_143222587-MSI_netfx_Core_x64.msi.txt
Final Result: Installation failed with error code: (0x80070643), "Fatal error during installation. " (Elapsed time: 0 00:00:09).
I can post a much longer version with all details if it's helpful. Can anyone offer advice?
PS - Microsoft Fix It tool does not find any errors so it won't resolve the issue and allow me to repair the .NET Framework.