Rule out the usual hiding places first. If the piece really is gone, check the set piece by piece
and leave with the element ID LEGO asks for, or a link to buy the part.
Builders who report a missing piece often find it in one of these places. Tick each one off as you look.
Look-alike colors in this set
These parts appear in this set in two colors that are easy to confuse. If you are one short in one color,
check whether it went in where the other color belongs. Each color has its own element ID in the parts list
at the back of the instructions.
Plate 1 x 4Black ×8Dark Bluish Gray ×3Black is darker than Dark Bluish Gray.
Plate 2 x 2Black ×4Dark Bluish Gray ×8Black is darker than Dark Bluish Gray.
Plate 2 x 3Black ×6Dark Bluish Gray ×7Black is darker than Dark Bluish Gray.
Tile 1 x 6 with GrooveBlack ×20Dark Bluish Gray ×4Black is darker than Dark Bluish Gray.
Tile 1 x 8 with GrooveBlack ×15Dark Bluish Gray ×2Black is darker than Dark Bluish Gray.
Technic Pin Long with Friction Ridges Lengthwise and Stop Bush [3 Lateral Holes, Big Pin Hole]Light Bluish GrayPart 32054Element 4211865×4
Technic Pin without Friction Ridges LengthwiseLight Bluish GrayPart 3673Element 4211807 or 36731942 spares in the box×4
Technic Rotation Joint Disk with Pin and 3L Beam ThickLight Bluish GrayPart 44225Element 6671155 or 6332151×2
Tile Special 1 x 2 Grille with Bottom GrooveLight Bluish GrayPart 2412bElement 4211350×5
Trans-Neon Green
39 pieces
Brick Round 1 x 1 Open StudTrans-Neon GreenPart 3062bElement 6514237 or 6238675×32
Cone 1 x 1 [No Top Groove]Trans-Neon GreenPart 4589Element 618849 or 458949×2
Plate Round 1 x 1 with Solid StudTrans-Neon GreenPart 6141Element 6240223 or 30057492 spares in the box×4
Windscreen 6 x 6 x 3 Canopy Half Sphere with Dual 2 FingersTrans-Neon GreenPart 50747Element 4500929×1
Trans-Dark Blue
34 pieces
Brick Round 1 x 1 Open StudTrans-Dark BluePart 3062bElement 6514233 or 6238044×32
Cone 1 x 1 [No Top Groove]Trans-Dark BluePart 4589Element 618843×2
Blue
6 pieces
Technic Axle Pin with Friction Ridges LengthwiseBluePart 43093Element 4309323 or 4206482×2
Technic Pin Long with Friction Ridges Lengthwise, 2 Center SlotsBluePart 6558Element 4514553×4
Dark Red
6 pieces
Plant / Creature Body Part, Vine / Tail / Tentacle / Bionicle Spine, SpikyDark RedPart 55236Element 4541488 or 4294145×2
Plate 1 x 1Dark RedPart 3024Element 4539114 or 4183901×4
Reddish Brown
2 pieces
Hood, Connected ChinReddish BrownPart 30381Element 4655372 or 4277666×1
Minifig Head [Plain] [Blocked Open Stud]Reddish BrownPart 3626b×1
[No Color/Any Color]
1 piece
Sticker Sheet for Set 10186-1[No Color/Any Color]Part 62621Element 4524038×1
Tick each piece as you find it, or mark it missing.
When a piece really is missing
Ask LEGO
LEGO takes requests for pieces missing from a new set through its customer service site. The form asks for
the set number and each piece's element ID, the number printed beside the piece in the parts list at the back
of the instructions. This checker lists both.
Mark a piece missing and your list links it to an eBay search for that part, which also covers pieces from
older or second-hand sets.
Keep a record
Copy or download your missing list (the CSV opens in any spreadsheet), or print the whole checklist and tick
pieces off on paper. Your marks stay in this browser, so you can check a big set over several sittings.