Fixing Error Code 0x800f0930: Installing .NET Framework 3.5 on Windows Server 2012

To resolve the error code 0x800f0930 when attempting to install .NET Framework 3.5 on Windows Server 2012, follow these steps:

1. Verify if .NET Framework 3.5 is already installed: Launch Server Manager, navigate to the 'Add Roles and Features' wizard, and see if the .NET Framework 3.5 feature is present. If installed, consider removing and then reinstalling it.
2. Utilize the DISM command: Open an elevated Command Prompt and execute: DISM /Online /Enable-Feature /FeatureName:NetFx3 /All /LimitAccess /Source:D:\sources\sxs (substitute 'D:' with your Windows Server 2012 installation media drive letter). This will install .NET Framework 3.5 directly from your media.
3. Update via Windows Update: Access the Windows Update settings and search for available updates. Should there be updates pertinent to .NET Framework, install them before attempting to install .NET Framework 3.5 once more.
4. Adjust Group Policy settings: If your server is connected to a domain, inspect the Group Policy settings for installing the .NET Framework. Ensure the 'Specify settings for optional component installation and component repair' setting is activated, and the 'Download repair content and optional features directly from Windows Update instead of Windows Server Update Services (WSUS)' setting is enabled.
5. Examine antivirus software: Interference from antivirus software might block the installation of .NET Framework. Temporarily disable your antivirus program and attempt the installation again.
6. Inspect the Windows Installer service: Verify that the Windows Installer service is active. Open the Services console to check the status of the Windows Installer service. If it is stopped, start it and proceed with the installation of .NET Framework 3.5.