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

To address the error code 0x800f0928 during the installation of .NET Framework 3.5 in Windows Server 2012, follow these detailed steps:

1. Verify .NET Framework 3.5 Installation: Navigate to the Server Manager and access the 'Add Roles and Features' wizard to check whether .NET Framework 3.5 is installed. If found, attempt a repair.
2. Apply the DISM Command: Launch Command Prompt with administrative privileges and execute: DISM /Online /Enable-Feature /FeatureName:NetFx3 /All /LimitAccess /Source:D:\sources\sxs (substitute 'D:' with the appropriate drive letter of your installation media). This operation fetches and installs the .NET Framework 3.5 from your media.
3. Utilize Windows Update: Access Windows Update settings and search for new updates. If updates for the .NET Framework are available, install them and attempt the .NET Framework 3.5 installation once more.
4. Adjust Group Policy Settings: For domain-connected Windows Server 2012 systems, ensure the Group Policy settings for .NET Framework installations are configured properly. Activate the 'Specify settings for optional component installation and component repair' and set the 'Download repair content and optional features directly from Windows Update instead of WSUS' to 'Enabled'.
5. Inspect Antivirus Interference: Some antivirus programs may block the installation of .NET Framework 3.5. Temporarily disable your antivirus software and try the installation again.
6. Examine Windows Installer Service: Confirm that the Windows Installer service is operational. Check its status in the Services console and start it if necessary to proceed with the .NET Framework 3.5 installation.
7. Check System Files: Utilize the System File Checker (SFC) tool to identify and fix corrupted system files. Open an elevated Command Prompt and run: sfc /scannow. This tool will inspect and repair damaged files, facilitating a smooth installation.