Check the box for .
: Secure corporate networks, server environments, and industrial computers are frequently disconnected from the public internet for safety.
Modern operating systems come pre-packaged with newer framework versions like .NET 4.8 or .NET 6.0/8.0. However, these newer versions are not natively backward-compatible with software built specifically for older environments. Check the box for
The .NET Framework 3.5 is essential for running many older desktop applications on modern operating systems. While Windows 10 and Windows 11 ship with newer versions like .NET 4.8 pre-installed, they do not enable version 3.5 by default. Attempting to install it online can sometimes fail due to network restrictions, Windows Update errors, or lack of internet access.
Right-click the downloaded file ( dotnetfx35.exe ) and select . Follow the on-screen prompts to complete the deployment. Troubleshooting Common Installation Errors Error Code 0x800F0906 or 0x800F081F Attempting to install it online can sometimes fail
If you try to use the standard installer and receive an error code like 0x800F0906 , it means Windows is struggling to find the source files offline. In this case, use Method 3 below, which uses a small utility to automate the offline installation process without needing a full Windows ISO.
Via DISM: (SSD) or up to 10 minutes (HDD). Via GUI online: 10–30 minutes depending on download speed. use Method 3 below
Mount the ISO file (right-click -> Mount) or plug in the USB stick. Note the drive letter (e.g., D: , E: , F: ).
The safest and most reliable "offline installer" is already in your possession if you have a Windows 10 or Windows 11 ISO file, installation DVD, or bootable USB flash drive. The actual payload files required for .NET 3.5 are located inside the sources\sxs folder of your Windows installation media. Step-by-Step Deployment:
Copy this file to a USB drive if you need to install it on an offline computer. Right-click the installer and select . Follow the on-screen prompts to complete the setup. Method 2: Install Offline Using Windows Installation Media
Click the button to save the standalone installer package ( dotnetfx35.exe ).