One of our clients recently lost a server due to a hard drive controller failure.  While RAID was enabled, the controller failure resulted in some odd corruption on the server.  After restoring all the necessary backups, we noticed that the .NET based applications would not launch.  Odd… .NET is installed, I can see the v2.0.50727 directory, it all seems to be installed.

Pulling out the old book of first line of support tasks, we

1st: we attempted to reinstall dotnetfx.exe (.NET 2.0)
This failed with the following error

Setup cannot continue because this version of the .NET Framework is incompatible with a previously installed one. For more information, see http://support.microsoft.com/kb/906894.

2nd: we attempted to uninstall the .NET framework via the Add/Remove programs function
This failed with a “cannot launch uninstall package”. 

3rd: we attempted to manually uninstall and reinstall the .NET framework via the Microsoft recommended methods documented at http://support.microsoft.com/kb/908077.  During the reinstall of dotnetfx.exe, we once again received the “Setup cannot continue because this version of the .NET Framework is incompatible…” error
(Side note:  Finding and downloading the MSICUU2.EXE tool proved to be remarkably difficult.  For future reference, I have included the installer file at this link)

Then we remember an article we read a couple of years ago about a .NET clean-up tool which works wonders on corrupted .NET installs.  The tools is available at

http://blogs.msdn.com/b/astebner/archive/2008/08/28/8904493.aspx

We ran the tool, reinstalled .NET and all was well on the server…. at least until next time