We know that from Windows Vista, the original optical media is useless after you finish system installation. Enabling a role of feature do not require that media any more.
But in Windows 8 / Windows Server 2012, for some reason we don’t know, the situation is changed a little. The setup package of dotNet framework 3.5 is not pre-copied to your hard drive. It will have to be downloaded from Microsoft while enabling that feature.
If you hate this, luckily, that setup package is on installation media also. We just need to tell the system to use that instead of downloading.
You may want to run this as administrator:
DISM /Online /Enable-Feature /FeatureName:NetFx3 /All /LimitAccess /Source:d:\sources\sxs
- /Online targets the operating system you’re running (instead of an offline Windows image).
- /Enable-Feature /FeatureName:NetFx3 specifies that you want to enable the .NET Framework 3.5.
- /All enables all parent features of the .NET Framework 3.5.
- /LimitAccess prevents DISM from contacting Windows Update.
- /Source specifies the location of the files needed to restore the feature (in this example, the D:\sources\sxs directory).