Before downloading the main software, use the Manager tool to update your dongle firmware.
Always open the driver installers and the EFT software with admin privileges.
To get your setup running perfectly, you need a combination of the smart card drivers and the specific mobile interface drivers. 1. Smart Card Driver
Plug the EFT Dongle into a USB 2.0 port (USB 3.0 can sometimes be unstable for flashing).
Since EFT supports thousands of models, you need the drivers for the phones you are servicing: Essential for Odin and Download Mode.