For Windows 10, the official and most reliable way to install .NET Framework 3.5 (64-bit) offline is to Windows 10 installation media (ISO or USB)
The quest began. Alex didn't want a "web installer" that would just fail again; the goal was the full package. Chapter 1: The Official Scroll
Although Windows 10 comes with the .NET Framework 4.6.1 or later versions pre-installed, some older applications may still require .NET Framework 3.5 to function properly. If you're trying to run an application that depends on .NET Framework 3.5, you'll need to download and install it separately. For Windows 10, the official and most reliable
Once the progress bar reaches 100%, you can verify it's active:
In this article, we’ll explain what this tool is, why you need the offline version, where to download it safely, and how to install it step-by-step. If you're trying to run an application that depends on
Warning: Do not download from third-party "download manager" sites. They often bundle malware or outdated versions. Always use official Microsoft sources.
Now you have a portable, permanent offline installer. They often bundle malware or outdated versions
You need access to the Windows 10 installation files.
This is the official recommended method for environments without internet access.