Installing .NET Framework 3.5 on Windows Server 2016 is a common requirement for legacy applications, but it often fails because the necessary binary files are not included in the default OS installation to save space. Unlike standard software, you don't typically "download" a standalone installer; instead, you enable it as a "Feature on Demand".
Enter the path: D:\sources\sxs (replace D: with your actual drive letter). Click and then Install . Method 3: PowerShell (Fastest Method) download framework 3.5 windows server 2016
PowerShell is often the most reliable way to force the installation using local media. Microsoft Learn Install .NET Framework 3.5 on Windows 10 - Microsoft Learn Installing