Find one laptop in each of the 18 campaign missions. Pick it up before finishing the level; the mission-select replay can recover anything missed.
All 18 file locations
1. Ghost Stories — After returning from space and crossing the car, enter the one-way house; check on the right near its exit.
2. Brave New World — After the MAAWS helicopter sequence and MATV ride, enter the base, go up to the third floor, and check the large table in the computer room.
3. No Man's Land — At the open area with the broken windmill, pass the enemies and enter the nearby building; the file is inside. IGN describes the landmark as the trailer by the crane and crashed satellite.
4. Struck Down — After breaching the slow-motion room, clear enemies, then inspect the lockers on the left as you entered (IGN: near the baseball shirts).
5. Homecoming — At the opening allied camp house, check the ground floor's left corner table before climbing the stairs.
6. Legends Never Die — After Rorke pulls you from the flood, cross the long platform and enter the opposite building; check where the two guards were standing.
7. Federation Day — After rappelling down and cutting into the tower, check the room to the left of the server-room objective; the laptop may be easier to spot from another angle in the dark room.
8. Birds of Prey — At the final Rorke room, grab the file from his desk immediately; the mission ends shortly after entry.
9. The Hunted — Near the regroup point up the hill, check beside the waterfall to the left of your teammates.
10. Clockwork — After the lights go out and night vision comes on, pass the security checkpoint and enter the accessible central office; check its table.
11. Atlas Falls — After the grapnel and common-room fight, reach the control room where your teammate handles the last guard; check the right side as you enter.
12. Into the Deep — After the torpedo strike and swim through the rusty tanker, clear the enemies and look slightly right on the seabed, on the first rock. PowerPyx notes the laptop takes a moment to sink into view.
13. End of the Line — In the large room with the satellite and rockets, go down the short stairs just after entering and turn around; the file is on a box.
14. Sin City — After the Egyptian-style casino, crouch under the gate your teammate raises and look immediately left in the seating area.
15. All or Nothing — Turn around at the start and inspect a bunk (IGN specifies the second bunk set on the left).
16. Severed Ties — After launching the missile, descend the stairs; when Hesh opens the door, turn right into the small side room and check the computer terminal.
17. Loki — After the space explosion and the two enemies, look left by the shiny orange/copper panel; the file floats, so collect it promptly.
18. The Ghost Killer — Turn around in the starting room and check the back corner for the final file.