Troubleshooting Error 0x800f0928: Installing .NET Framework 3.5 on Windows Server 2012

Follow these effective methods to address error code 0x800f0928 during .NET Framework 3.5 installation on Windows Server 2012:

1. Verify .NET Framework 3.5 status: Access Server Manager, navigate to the 'Add Roles and Features' wizard. Confirm if .NET Framework 3.5 is installed. If found, attempt a repair.
2. Apply the DISM tool: Launch Command Prompt with administrative rights and execute: DISM /Online /Enable-Feature /FeatureName:NetFx3 /All /LimitAccess /Source:E:\sources\sxs (amend 'E:' as needed for your setup). This command uses your installation media to enable .NET Framework 3.5.
3. Utilize Windows Update: Navigate to Windows Update settings, check for available updates particularly for .NET Framework, and apply them before trying the .NET Framework 3.5 installation again.
4. Adjust Group Policy settings: If your server is under a domain, review the Group Policy settings for .NET Framework setup. Ensure the 'Specify settings for optional component installation and component repair' policy is enabled and that 'Download repair content and optional features directly from Windows Update instead of from Windows Server Update Services (WSUS)' is also enabled.
5. Temporarily disable antivirus software: Some antivirus programs may block the .NET Framework installation. Disable your antivirus temporarily and try the installation again.
6. Ensure the Windows Installer service is active: Open the Services console to verify that the Windows Installer service is operational. If it is not running, start it and proceed with the .NET Framework 3.5 installation.
7. Run System File Checker (SFC): Open Command Prompt as an administrator and execute: sfc /scannow. This will scan and potentially repair any corrupted system files that might impede the installation.