A navcomputer virus was a computer virus that disabled a ship's navicomputer, making it impossible to guide through real- or hyperspace.
During the Stark Hyperspace War, the Stark Collective developed a navcomputer virus which they transmitted to Ranulph Tarkin's paramilitary by piggybacking the signal to Nute Gunray's location-finder. The virus caused a third of Tarkin's fleet to jump into areas that would destroy ships (such as inside planets or stars); a third to emerge in realspace safe but scattered throughout the galaxy; and only a third to reach Troiken.
Decades later, the navcomputer virus was adapted to the Iron Eclipse project.