As a matter of practice, I always install .NET updates separately by themselves after installing all other updates and patches for the OS. I cannot remember the last time I had a .NET installation failure doing it that way.
When folks encounter repeated issues with installing .NET Framework (updates, applying a hotfix or service pack), I generally recommend following the instructions provided by Aaron Stebner
in his Blog article What to do if other .NET Framework setup troubleshooting steps do not help
. Aaron works for Microsoft, answers questions at the MSDN forums and writes about .NET Framework issues on his Blog.
1. If repairing the version of .NET Framework that is causing the problem does not work, Aaron recommends using the Microsoft .NET Framework Repair Tool
(NetFxRepairTool.exe) which detects and tries to fix some frequently occurring issues with the setup of or with updates to the Microsoft .NET Framework 4 and .NET 3.5 SP1 (includes .NET 3.0 SP2 and .NET 2.0 SP2).
2. If the repair tool does not help, Aaron next advises to go to the Add/Remove or Programs and Features in Control Panel and uninstall the version of the .NET Framework that is causing problems. If uninstall still fails read the .NET Framework Cleanup Tool User's Guide
, download the .NET Framework cleanup tool and remove the version of the .NET Framework that is causing problems.
3. If the above steps do not resolve the problem, then uninstall all versions of .NET Framework and before reinstalling, read Aaron Stebner's
Blog article Should I re-install the versions of the .NET Framework in a specific order?
Many installation issues with .NET Framework software are often the result of the how the various versions of the software is installed. Although .NET Framework versions can be installed in any order, Aaron recommends to install .NET Framework in reverse order
from the most current to the oldest. He advises this because the most current version includes the the latest updates of files shared by all versions so that helps to eliminate some bugs and installation issues.
All .NET Framework versions are available for download separately from Microsoft's download center
so you can bypass Windows Update. If a version is not listed, simply type the version name in the the Search box at the top. Aaron also has download links on his Blog for the various .NET Framework versions.