Enabling .Net 3.5 in your windows 8 Image

This blogpost covers how to enable .Net 3.5 in your windows 8 wim file and saves you the trouble of running DISM after deployment (or during) to enable it.

Note - This blogpost assumes that you are running this on a windows 8 / server 2012 machine.

First copy the contents of your Windows 8 ISO to a Directory on a drive (Lets call that "C:\Windows 8 Source" here)

Create a folder on your C: drive called "MountedWim"

Now open up an administrative command prompt and type the following:

Dism /Mount-Wim /Wimfile:"C:\Windows 8 Source\Sources\Install.wim" /index:1 /MountDir:C:\MountedWim

This will  mount the windows 8 wim file into this directory

Now type the following:

Dism /Image:C:\MountedWim /EnableFeature /FeatureName:NetFX3 /All /Source:"C:\Windows 8 Source\Sources\sxs"

This will enable .Net 3.5 in the image however we now need to save the changes we have made, next type:

Dism /UnMount-Wim /MountDir:C:\MountedWim /Commit

This will unmount the wim file and commit the changes.

Now deploy the image and you should have .Net 3.5 enabled by default :)

A quick "gotcha" on this, if you use offline servicing in configuration manager to integrate any .Net 3.5 updates into this wim since the .Net 3.5 install is in a "Pending" state your Task Sequence will fail, so watch out for that.

Cheers
Wayne