Windows Server 2008 and .NET Framework versions. A bit like the Matryoshka doll

You know Matryoshka? The Russian nested doll. One big doll contains a smaller one and so on. Since one picture says more than a thousand words:

The same thing can be said about .NET Framework on Windows Server 2008 where version 3.0 is installed as a Feature:

But this version contains ALSO version 2. Even though it is not to be seen in Programs and Features in the Control Panel, under water this version is present. Go check it out your self in the folder: ‘C:\Windows\Microsoft.NET’. There are two folders present. One for the 32 bits architecture and one for the 64 bits architecture. Check the x64 folder and this is what you will see:

Okay, you have made your point. So what?

Suppose, you run into an issue with OpsMgr where high handle counts on the Management Servers (or servers with an OpsMgr Agent) are found. These servers are x64 based. It will finally result in your Management Server(s) and/or RMS ending up with a red flag: a critical Alert will be raised about a handle count which is way too high.

This can be caused by a issue with .NET Framework 2 SP2. For this Microsoft has released a hotfix, to be found here: http://support.microsoft.com/default.aspx/kb/968760. This hotfix also applies to Windows Server 2008 SP2!

This hotfix does NOT apply to Windows Server 2008 R2.

So far so good. Suppose the servers are Windows 2003. No problem what so ever. But what when your servers are Windows 2008 based? As long as your .NET Framework is up-to-date, no worries. But suppose you have installed .NET Framework 3.0 as a Feature and haven’t updated it since?

The installation of the hotfix will NOT run since it needs SP2 for .NET Framework 2.0 to be in place. OK. So you try to install SP2 for .NET Framework 2.0? Nope. Won’t do either. But still, SP2 needs to be in place. Otherwise the hotfix will not install. This is the way to go:

You already installed .NET Framework 3.0 (contains version 2.0 as well) as a Feature > install .NET Framework 3.5 SP1 (contains SP2 for version 2.0 as well) > install the hotfix.

Advise:
Keep .NET Framework updated on all your servers all the time. Newer versions will be installed alongside previous versions. So software depending on a particular version is most likely not to be affected. Many times, newer versions contain updates/SPs for previous versions as well. These updates/SPs are important.