This error when you try to install Microsoft .Net Framework 3 or 3.5 on a server running Windows Server 20012 R2.
Using Windows Server 2012 RC from the VHD, and selecting the .NET Framework 3.5 Feature, gives error message “The source files could not be found”
This issue continues even if you manually download the application and try to install it.
To solve this issue, you need to install the .Net 3.5 framework from the Windows 2012 R2 installation DVD. The files are located on “Source\sxs”.
Note: To improve the speed you can copy the files from the DVD to any folder on the server.
For this example, the files were copy to “C:\temp\sxs”.
Open a CMS windows as an “Administrator” and paste the following command:
C:\Windows\system32>dism.exe /online /enable-feature /featurename:NetFX3 /Source :C:\temp\sxs /LimitAccess /all
Note: Modify the /Source attribute if needed.
If the process was successful, you will see the following message