How To Activate the .NET Framework 3.5 on Windows 8 Without Internet Access

One of the prerequisites for a complete SQL Server 2012 installation is that the operating system has the .NET Framework 3.5 installed.  As you might know, Windows 8 has the .NET Framework 4.5 built-in and you can optionally activate .NET Framework 3.5 using the Windows Features panel (see the image below), but the problem is that once you activate the .NET Framework 3.5 the computer will want to access to Microsoft servers on the Internet to get the binaries.

But what do you do if you have no Internet connection?  The solution emerges with the Windows 8 ISO and DISM.  Have a look below and check this quick step-by-step guide on how to activate the .NET Framework 3.5 without Internet access:

1.     Create a folder under your system drive called net35 (example: C:\net35)
2.     Mount your Windows 8 ISO file
3.     In the Windows 8 ISO, copy the folder “sources\sxs\” into the newly created net35 folder. I recommend using xcopy for it: xcopy DRIVERLETTER:\sources\sxs\*.* c:\net35 /s.
4.     Once you copied all the files, you now utilize DISM to enable the .NET Framework 3.5 feature by entering the following command in an elevated command prompt:

 DISM.exe /online /enable-feature /featurename:NetFX3 /All /Source:c:\net35 /LimitAccess

If everything runs smoothly you now should have the .NET Framework 3.5 activated with a computer not having access to the Internet.