.NET Framework 4.5 (or higher) is often built into modern Windows versions; if a program asks for it, you can typically enable it via "Turn Windows features on or off" in the Control Panel. Why Use the Offline Installer?
– The installer will copy files, modify the registry, and optimize system performance. On a standard HDD, this takes 5–10 minutes. On an SSD, 2–4 minutes. microsoft net framework 4.5 offline installer
It is also worth addressing common misconceptions. Users sometimes believe the offline installer is obsolete because Microsoft encourages web deployment. However, the company itself provides offline installers for all major .NET versions via the Microsoft Download Center. Furthermore, the offline installer is not a replacement for Windows Update security patches; it installs the base version. Administrators should still apply relevant security updates afterward. Another misconception is that the offline installer contains the full software development kit (SDK)—it does not; it only contains the runtime and class libraries needed to run applications, not to compile new ones. On a standard HDD, this takes 5–10 minutes
The .NET Framework 4.5 introduced several transformative updates for the ecosystem: Users sometimes believe the offline installer is obsolete
If your file doesn't match, do not run it.