Your PC is managed by an IT admin who disabled feature installation from untrusted sources. Fix: Run gpedit.msc > Computer Config > Admin Templates > System > Specify settings for optional component installation > Set to Enabled and allow the source.

You downloaded a .cab from a wrong architecture (32-bit instead of 64-bit) or Windows build mismatch. Fix: Extract the CAB directly from a Windows 10 64-bit ISO that matches your version (21H2, 22H2, etc.).

By default, Windows 10 is configured to missing features from Windows Update. If your internet connection is unstable, if you are on a domain-joined PC without WSUS, or if Microsoft servers are slow, the progress bar sticks at 47.2% or 65.8% and then rolls back. The offline installer bypasses this entirely.

The same method applies to Windows 11 64-bit. Use a Windows 11 ISO’s sxs folder.

Net Framework 3.5 Offline Installer Windows 10 64 Bit