VMware vCenter Server 5.x Install on W2K12 Fix: The following feature couldn’t be installed: .NET Framework 3.5

A pre-requisite of installing VMware vCenter Server 5.x is for the Microsoft .NET Framework (3.5). When recently installing VMware vCenter Server v5.1 on a new Microsoft Windows Server 2012 VM in my vSphere lab I had forgotten to install this pre-requisite and was presented with the following information box: “The following feature couldn’t be installed: .NET Framework 3.5 (includes .NET 2.0 and 3.0)”.

How to Resolve

The message given when installing VMware vCenter Server on a Windows Server 2012 (W2K12) OS isn’t to be unexpected as Microsoft also documents that this is an issue that can occur on W2K12 when the .NET Framework 3.5 tries to be installed from an installation wizard, see here for more details on what causes the problem.  Note:  I recommend that you install any pre-requisites ahead of starting the vCenter Server install.

I had tried installing it via the “Windows Server roles and features” GUI method although this unfortunately just didn’t take for some reason.

To get around this problem I simply performed a command-line installation, which worked successfully for me.

Note:  The “Source”  shown in the command below should be changed to the location of the Windows Server 2012  installation disc. As you can see my source was: d:\sources

dism /online /enable-feature /featurename:NetFX3 /all /Source:d:\sources\sxs /LimitAccess

Useful Link:

Microsoft Support:  “Error codes when you try to install the .NET Framework 3.5 in Windows 8 or in Windows Server 2012”