Resolving Error Code 0x800f0831: Installing .NET Framework 3.5 on Windows Server 2016

To address error code 0x800f0831 while attempting to install .NET Framework 3.5 on Windows Server 2016, follow these steps:

1. Verify existing installation of .NET Framework 3.5: Navigate to the Control Panel, proceed to Programs and Features, and search for Microsoft .NET Framework 3.5 to see if it’s already on your system. If found, no further installation is required.
2. Execute the DISM command: Launch Command Prompt with administrative privileges and enter: DISM /Online /Enable-Feature /FeatureName:NetFx3 /All /LimitAccess /Source:D:\sources\sxs. Change 'D:' to the drive letter of your Windows Server 2016 installation media. This will initiate the .NET Framework 3.5 installation from your media.
3. Utilise the Windows Server 2016 installation media: Place the Windows Server 2016 media into the drive and navigate through File Explorer to the Sources directory to locate the 'sxs' folder. Copy this folder either to your desktop or another preferred directory on your server. Then, run Command Prompt as an administrator and input: Dism /online /enable-feature /featurename:NetFx3 /All /LimitAccess /Source:C:\sxs. Substitute 'C:' with the drive letter where you’ve stored the 'sxs' folder.
4. Ensure the latest Windows updates: Check that your Windows Server 2016 system is updated by going to Settings > Update & Security > Windows Update. Search for new updates, install them, and try the .NET Framework 3.5 installation once more.
5. Temporarily disable antivirus software: At times, antivirus programs may obstruct the installation process of .NET Framework 3.5. Consider deactivating your antivirus software briefly and attempt the installation again.