Leo grabbed his phone and searched: download net framework 3.5 windows 10 64 bit offline installer . He immediately saw the trap: shady "driver download" sites promising the file but stuffed with adware. He almost clicked one, but then he remembered his IT friend, Maria.

The safest way to acquire the standalone package for environments that eventually connect to the internet, or for transferring via USB drive, is through the official Microsoft download portal. Navigate to the official Microsoft Download Center.

Click the button to save the bootstrapper or full package ( dotnetfx35.exe ).

Windows 10 already contains the payload files for .NET Framework 3.5 inside its installation media. You can use your original Windows 10 64-bit ISO file or installation DVD to install the feature offline via the Deployment Image Servicing and Management (DISM) tool. Step 1: Mount the Windows 10 ISO Locate your Windows 10 64-bit ISO file. Right-click the ISO file and select .

Reliable, secure, and designed specifically for Windows 10.

Note: The /Source:D:\sources\sxs part assumes his USB drive is D: . If his drive was E: , he changed it to E: .

He right-clicked the Start button, chose Windows Terminal (Admin) or Command Prompt (Admin) . The blue "Yes" UAC prompt popped up. He clicked Yes.

Type or paste the following command into the prompt (replace E: with the actual drive letter of your mounted ISO):

Local installation from a USB drive or local disk is significantly faster than downloading files from external servers. Prerequisites Before Installation

This error usually happens when advanced security tools or group policies block feature installations.