I need to to install Net Framework 3.5 SP1 on Server 2012 and I know of the method which requires the installation media. Installing .NET framework 3.5 on windows server 2012

However, I do not have the installation media and no Internet. Is there any other way of installing it?

  • Extract it using the DISM tool to a folder location with a computer that does have access a installation media and/or access to the internet. Once it is placed into the component store it can be extracted. – Ramhound Dec 10 '14 at 17:41
  • Possible duplicate of Installing .NET framework 3.5 on windows server 2012 – eis Mar 9 '16 at 15:00

You can download the Windows Server 2012 trial version to get an ISO with the required source files.

Mount the ISO with the inbox ISO mounting and run DISM to install .Net 3.5:

dism.exe /online /enable-feature /featurename:NetFX3 /Source:d:\sources\sxs /LimitAccess

If it fails, also try to run this Update before trying to activate .Net 3.5:

Update for the .NET Framework 3.5 on Windows 8, Windows 8.1, Windows Server 2012, and Windows Server 2012 R2


This removes 2 security updates which may prevent setup of .Net 3.5

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  • 2
    That was a great idea, but it failed saying it couldn't find the source files. I did check and it was D:\sources\sxs too. I also added the /all flag. – drum Dec 10 '14 at 21:10
  • you have edited your question. For R2 you have to download the R2 ISO – magicandre1981 Dec 11 '14 at 17:03
  • 1
    I did download the R2 trial version. – drum Dec 11 '14 at 19:57
  • Do you have any MUI Packs installed? – magicandre1981 Dec 12 '14 at 5:16
  • None. It's a fresh install with only the C++ redistributables. – drum Dec 12 '14 at 14:39

This answer combines information from multiple answers and also adds some extra steps not previously mentioned.

I managed to do it in the following way:

  1. Download the ISO image for Windows Server 2012 R2 (Note! has to be R2) from https://www.microsoft.com/en-us/evalcenter/evaluate-windows-server-2012-r2 . It needs a windows live id registration and you need to agree to follow-up emails.
  2. Once you've downloaded it to some location, transfer to the machine/VM you wish to install it to.
  3. Copy it to another location within the target machine. This is to prevent "sorry, there was a problem mounting the file" error as described here, which relates to some transfer managers writing the file as sparse files. If you actually copied it already during the transfer in the previous step and not just mapped it, this step might not be needed: for me it was.
  4. Right click the file in explorer and select "Mount". It should be mounted, I'm assuming to D: drive. If you get an error, revert to previous link.
  5. Open cmd prompt as administrator and run the following commands (switches are explained in this other answer in a similar thread):


dism.exe /online /enable-feature /featurename:NetFX3ServerFeatures /all /Source:d:\sources\sxs /LimitAccess
dism.exe /online /enable-feature /featurename:NetFX3 /all /Source:d:\sources\sxs /LimitAccess

Both seem to be needed and in the order I've given. (source)

If you get an error "source files not found", reconfirm you have R2 image in use. That was the problem for me - the actual .NET 3.5 was missing from my image, which was plain 2012.

If both commands are successful, congratulations! You now have it installed. In case you're in doubt, you can confirm the version using steps outlined here.

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  • 2
    For me it seems /all is only recognized when it follows /featurename. – i did not pay the royalties Apr 10 '17 at 13:32
  • This was perfect for me. My server is virtual and I didn't have access to the original DVD. The comment above me is also correct. – Ethan Allen Oct 5 '17 at 5:22
  • ok, moved /all after /featurename as suggested here. – eis Jan 24 '19 at 7:01

Here's how i did it.

Download the ISO image for Windows Server 2012 R2 from https://www.microsoft.com/en-us/evalcenter/evaluate-windows-server-2012-r2 .

Put that Disc image on the computer that needs .Net Framwork 3.5

Right Click on the file and mount. This should create a D drive. Go to Server Manager, click Manage > Add roles and Features.

Click through to the Features selection and choose the .Net Framework 3.5 entry.
Keep clicking Next until you get to the final page.

Don't click Install yet- Click the small link at the bottom to "Specify Alternate Data Source." Change the path to be D:\Sources\SxS

Then install

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  • This is very similar to other answers here. Can you expand a little on what is different with your answer? – Burgi May 26 '16 at 20:37
  • This worked perfectly for me. A group policy on the particular machine forbids downloads from Windows Update, so I had to point to the DVD image. – j8048188 Jul 7 '17 at 23:36

The only way I managed to install the framework is by connecting the machine to the internet and doing a Windows Update.

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For Windows 2012R2, the command should be

dism.exe /online /enable-feature /featurename:NetFX3ServerFeatures /Source:d:\sources\sxs /LimitAccess
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  • 1
    This was already suggested a year ago. how is your answer any different? – Ramhound May 26 '15 at 3:11
  • It should be "/featurename:NetFX3ServerFeatures" rather than "/featurename:NetFX3" – superlee May 26 '15 at 3:26
  • I tested the command. It installed the server features just fine, but .NET framework is not installed by that. According to this, NetFX3 feature should be installed after that, but that again gives "source files not found". – eis Mar 9 '16 at 12:54

Get a windows iso image 2008 server or higher mount the image to the inbuilt image drive of windows server 2012 r2, proceed to add roles and features and select the dotnet framework 3.5 feature, click alternatives source to show the path name eg e:\sources\sxs and click install. This should work.

Or run windows update and follow this https://support.microsoft.com/en-us/kb/3005628 for solution.

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  • For me this was the easiest, basically use the "Add Roles and Features Wizard" easily reached from Server Manager, with an alternative source. Thanks! – Konstantin Feb 21 '17 at 8:00

I specified C:\Windows\WinSXS as the alternate source path. This will fail half the time on the first go round, but it seems to eventually work.

I did it this morning with no issues and it completed on the first try.

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If mounting a https://www.microsoft.com/en-us/evalcenter/evaluate-windows-server-2012-r2 still fails, We determined a minor tweak to Eis's SUPERB INSTRUCTIONS March 19th/2016 was the last inch for success.

Downloading and mounting 2012 Server R2 install ISO is key, but we had to switch to the mounted drive letter\sources directory and load the NEWER R2 v9600 version of the DISM executable. Just mounting the ISO and specifying the /source location failed to complete or even initiate any progress of installation since Windows was using the version 9200 of DISM that apparently hates the /source switch but only reported as much inside the %systemroot%\Logs\DISM\dism.log. The error explicitly described /sources as and UNKNOWN switch and thus was doomed to silent failure without properly mounting the R2 source ISO.

It was necessary to hard specify the newer version of DISM.exe 9600 inside the mounted ISO by changing directories to the mounted ISO path of dism.exe.

cd /d d:\sources && .\dism.exe /online  /enable-feature    featurename:NetFX3ServerFeatures **/Source**:d:\sources\sxs /LimitAccess
cd /d d:\sources && .\dism.exe /online  /enable-feature /featurename:NetFX3 **/Source**:d:\sources\sxs /LimitAccess

The command processor output will immediately specify whether you're executing the required version of dism.exe

*Deployment Image Servicing and Management tool

**Version: 6.3.9600.17031**

Image Version: 6.2.9200.16384

Enabling feature(s)


The operation completed successfully.

Restart Windows to complete this operation.

Do you want to restart the computer now? (Y/N) n*

This was executed on a freshly turned up 2012 Server with only the Windows Update Agent v2 installed:

Windows Update Agent 7.8.9200.16927
Windows Update Agent 7.8.9200.16924

Windows Update Agent 7.8.9200.16927
Installation date: ‎01‎31‎2017 1304PM
Installation status: Succeeded
Windows Update Agent 7.8.9200.16927
Installation date: ‎01‎31‎2017 1304PM
Installation status: Succeeded

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