Windows 8 and Server 2012 come bundled with Microsoft .Net Framework 4.5, but for “legacy” .Net compatibility, you may need the .Net Framework 3.5 which provides 2.0, 3.0, and 3.5 versions. One popular tool that requires .Net 3.5 is SQL Server Management Studio 2012. There are quite a few other tools that require the old .Net versions.
If you’re lucky, you can add .Net 3.5 from the “Programs and Features” tool and it will install automatically by downloading the necessary packages from Microsoft. Unfortunately, many of us on corporate networks with group policies and WSUS (update servers) are experiencing problems installing .Net 3.5 through the GUI.
The errors I was getting on Server 2012 include: “error enabling windows feature NetFx3 error code -2146498298,” “Error installing Microsoft .NET Framework 3.5,” “source files could not be found – specify an alternate source path.”
To resolve this issue, I was able to follow instructions similar to those on the following article “Installing the .NET Framework 3.5 on Windows 8 [& 2012]” (msdn.microsoft.com) under the “Troubleshooting” section. Here are some hints I used for the install.
- Copy Windows install media ISO file to the system needing .Net 3.5
- Right-click the ISO file and choose “Mount”, take note of the drive letter assigned
- Open an administrative command prompt and use a command like the following (from the above article). Use the correct path for your install media source files (mounted ISO). Note: DISM stands for “Deployment Image Servicing and Management”.
- DISM /Online /Enable-Feature /FeatureName:NetFx3 /All /LimitAccess /Source:d:\sources\sxs
- Error codes when you try to install the .NET Framework 3.5 in Windows 8 or in Windows Server 2012 (support.microsoft.com) – includes Group Policy settings and other steps that might fix the problem