1. Droid PositionClabburn Tundra, in the center of the map, at the top of the hottest point of planet Hoth. It is a small earth crack from where lava is coming out.
2. Droid PositionClabburn Tundra, Southeastern part, bellow the ice bridge.
3. Droid PositionHighmount Ridge, at the top of the tall structure, west from Leth Outpost.
4. Droid PositionHighmount Ridge, Southern part, on the top of a wrecked spaceship.
5. Droid PositionThe Starship Graveyard, Northeastern part, on the top of the broken spaceship part which sticks out from the ground.
6. Droid PositionThe Starship Graveyard, Southern part, inside a back motor engine.
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.