Fixing the 0x800f0926 Error: Installing .NET Framework 3.5 on Windows Server 2012

To address the error code 0x800f0926 while attempting to install .NET Framework 3.5 on Windows Server 2012, follow these key steps:

1. Verify .NET Framework 3.5 status: Navigate to Control Panel > Programs and Features > Turn Windows features on or off. Ensure that .NET Framework 3.5 is not pre-installed.
2. Employ the DISM command: Launch Command Prompt as an administrator 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 command facilitates the installation of .NET Framework 3.5 from your media.
3. Run the Windows Update Troubleshooter: Access Control Panel > Troubleshooting > System and Security > Fix problems with Windows Update, and comply with the instructions to remedy issues related to Windows Update.
4. Manually download and install .NET Framework 3.5: Visit the Microsoft Download Center, download the .NET Framework 3.5 setup file, and follow the prompts to complete the installation.
5. Inspect for system file errors: Open Command Prompt as an administrator and input: sfc /scannow. This scan checks for and repairs corrupt system files if found.