By Deepak Bhardwaj Problem SQL Server failed to Enable OS Feature NetFx3 The following error has occurred: Error while enabling Windows feature: NetFx3, Error Code: -2146498298, Please try enabling Windows feature: NetFx3 from Windows management tools and then run setup again. For more information on how to enable Windows features, see http://go.microsoft.com/fwlink/?linkid=227143 Cause We did not enable .NET Framework 3.5 before installing SQL Server 2012 RC0. Setup tried to enable it but failed. By Deepak Bhardwaj Solution Follow the below process to Enable the .Net Frame Work 3.5. Step 1 On the new Server Manager of Windows Server 2012, Click on the Manage Menu and selected the option "Add Roles and Features". By Deepak Bhardwaj Step 2 On the first page of Add Roles and Features Wizard. Click on the Next button. By Deepak Bhardwaj Step 3 On the installation type page, chose "Role-based or feature-based installation". By Deepak Bhardwaj Step 4 On the Server Selection page of the wizard, select the actual server where we were installing SQL Server 2012. Step 5 On the "Features" page of the Wizard, click on the checkbox next to ".NET Framework 3.5 Features", and then clicked on the Next button. By Deepak Bhardwaj Step 6 On the confirmation page, click on the Install button. Note: When I tried to install the .Net Framework 3.5 using above process its failed. Then I come to know that it is failed due to non-availability of binaries available in the system. In that case we have to insert or mount Windows Server 2012 server CD in drive.Once ISO file mounted in Server or CD inserted in CD-ROM follow the below process. By Deepak Bhardwaj Step 1 Insert your Windows Server 2012 media or map Windows Server 2012 ISO. Step 2 Open Command Prompt with administrative credentials.From the Start Screen I typed CMD but instead of clicking on it or pressing ENTER I right-clicked, and at the bottom clicked on Run As Administrator. Step 3 From the Command Prompt I typed the following command: dism /online /enable-feature /featurename:netfx3 /all /source:d:\sources\sxs Screen-Shot is given below: Note: After successful message, start the SQL server installation processagain. By Deepak Bhardwaj Once Database installation completed you will recevice the below screen.