1. Droid PositionMinimum Security Section, Northwestern part, inside a watchtower in the center of the compound courtyard.
2. Droid PositionMaximum Security Section, North part, at the top of a rock that emerges from lava.
3. Droid PositionMaximum Security Thoroughfare, as soon as you enter the tunnel from Maximum Security Section, you can spot a droid in the distance.
4. Droid PositionAncient Prison Caverns, Southwestern part, on the second floor, behind a power shield.
5. Droid PositionThe Tomb, Northern part of the map, above the world boss Primal Destroyer, in the crack of the roof.
6. Droid PositionThe Tomb, right above the entrance of the Temple, at eastern part of the map.
Source: Official MCR-99 droid locations (hidden planetary achievements), MCR-99 Droid Locations post 2.0 on Swtor official Forums. We would like to thank SWTOR community members for all additional information.