If you’ve been working with Windows Server 2012/2012 R2 you might have noticed that you need the CD/install files handy if you want to install .NET 3.5. Which causes problems if you need that feature on an Azure VM. After a bit of digging I found this in the MSDN forums, and it has proven to be handy. I haven’t tried it enough to say that it is foolproof, but if you’re having this issue it’s worth a shot.
1. Go to Windows Update through the Control Panel.
2. Click “check for update” on the left side. It may take a while to check for the update like it did on my machine. (~5-10 min)
3. Click the “# important update is available” blue button next.
4. On the next screen you will be shown important updates that are ready to be installed. You should have an update called “Update for Microsoft .NET Framework 3.5 for x64-based Systems (KB3005628)”. With that update checked, click install on the bottom. There will be other updates available to you as well. I haven’t thoroughly tested for any combinations that specifically do/don’t work, so try at your own risk!
Assuming that update successfully install, lets go back to Server Manager and try the installation.
1 Go back to your Server Manager and in the top right corner click Manage -> Add Roles and Features.
2. Click next 4 times until you get to Features. Once in features check the box for “.NET Framework 3.5 Features” and then click next on the bottom.
3. On the next page if you see the yellow warning box to specify an alternate source path, just click ‘x’ to dismiss it. On the bottom of the page then, click install. If all goes well you should eventually see that installation succeeded.
If you’d like more detail on the why’s and wherefores:
UPDATE: Here’s an blog by an Aussie friend of mine that addresses a this issue in a non-Azure environment.
If you’re fighting this battle, definitely worth a read.