Multi-part RAR files work as a single unit. You cannot extract just part3 on its own.
Ensure you have every part in the same folder (e.g., part1.rar , part2.rar , part3.rar , etc.). Destroy_All_Humans_2_Reprobed-FLT.part3.rar
If there is a folder named FLT inside the mounted drive, copy its contents and paste them into the main installation directory of the game (where the game's .exe is located), replacing the existing files. 3. Gameplay Guides & Resources Multi-part RAR files work as a single unit