Depending on the patch status of the WSUS servers, you may not be able to install .NET 3.5 on Windows 8 or Windows Server 2012. To fix this via GUI, follow these steps:
Mount the .iso or insert the dvd for Windows 8 or Server 2012, whichever one matches the OS on your computer.
Server 2012
- Go to server manager and run the Add Roles and Features wizard
- Hit next, accepting all defaults, until you reach the ‘Features’ page
- Select .NET Framework 3.5 Features, then select Next
- Select Specify an alternate source path
- Enter the path to the SxS directory
Ex: D:\Sources\SxS\
Ex: \\ServerName\ShareName\Sources\SxS\ - Select OK, Install
Windows 8 or Server 2012
- Insert the Windows 8 or Windows Server 2012 installation media.
- At an elevated command prompt, run the following command:
Dism /online /enable-feature /featurename:NetFx3 /All /Source:<drive>:\sources\sxs /LimitAccess
Note In this command, <drive> is a placeholder for the drive letter for the DVD drive or for the Windows installation media. For example, you run the following command:
Dism /online /enable-feature /featurename:NetFx3 /All /Source:D:\sources\sxs /LimitAccess