In this Blog Post, let us see how to fix this Weird error message you might get while Installing SQL Server 2012 on top of Windows Server 2012. I already mentioned about this in the post where I showed how to Install SQL Server 2012 on Win Server 2012, but wanted to come up with a separate post just for this Error because it’s so annoying and frustrating when you see this. Trust me guys…This Error needs special Attention 
Okay, Let’s say you are all ready for deploying SQL Server 2012 on top of Windows Server 2012 as your boss is pushing you towards SQL Server 2012(Which is awesome ). You started your Installation and somewhere in the middle of your Installation Process, you get this annoying message that Installation Failed. Well, you are on Windows server 2012 which comes with brand new .Net Framework and you are not expecting any framework Issues(Initial setup Checklist gives no Errors on this). So what is it missing? The Answer is “.NET 3.51 Payload“. Yes, we must manually enable .NET 3.51 Payload in Windows Server 2012.
Look at the below Screenshot carefully at the Bottom left where it is asking for .Net Framework 3.5 to be enabled.
So, now you know why we need to pay attention while Installing SQL Server 
Anyways…..For this you need to have Windows media handy or should be connected to Internet, OR you can enable this automatically by enabling Remote Management which you might not do on your Production Boxes.
So, How to Fix this Annoying thing? Yes, you are correct if you said PowerShell (Few of you might thought about DISM or Just GUI for adding this feature as you used to do in Win Server 2008R2….YMMV!)
Note: Even the Error Message says, go and enable this feature using Server Manager GUI, it might fail!!!….Avoid GUI for fixing this. Instead use awesome PowerShell guys. I’ll show you powershell way of doing this…
1. Insert your Windows Media in your DVD Drive(in My case it’s D:)
2. Open Powershell as Admin and type “Install-WindowsFeature Net-Framework-Core -Source D:\Sources\sxs” without double Quotes and hit enter.
Look for Exit Code “Success”! That’s it Guys…The Rest should be Flawless!
