If you have the Windows 10 or 11 ISO, mount it. Navigate to the \sources\sxs folder.
These usually mean DISM cannot find the source file. Double-check that your /Source path is exactly where the .cab file is located and that the file name matches exactly. Microsoft-windows-netfx3-ondemand-package.cab Download
While many tech forums host this file for direct download, always verify the file hash or scan it for malware. Using the file from your official Windows ISO is the only 100% secure method. How to Install the .NET 3.5 CAB File (Step-by-Step) If you have the Windows 10 or 11 ISO, mount it
Open the , type cmd , right-click it, and select Run as Administrator . and select Run as Administrator .