If you cannot enable .NET 3.5 through "Turn Windows features on or off," you can use the DISM tool to point directly to the sources\sxs folder on your Windows 8 installation media.
The System File Checker tool scans and replaces corrupted system files. sxsi x64 windows 8
By the time Windows 8 arrived (2012), the SxS technology was mature, complex, and fully integrated into the 64-bit ecosystem. For developers working on x64 Windows 8, understanding SxS isn't just about manifests; it's about memory layout, processor affinity, and the %windir%\WinSxS folder—which on a typical Windows 8 x64 machine can easily balloon to 15-20GB. If you cannot enable