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.
Panel Curved Tapered with Bars at Each EndBright Light YellowPart 65783Element 6426173×4
Plates
4 pieces
Plate 2 x 3WhitePart 3021Element 6550136 or 302101×4
Technic Pins
4 pieces
Technic Axle Pin with Friction Ridges LengthwiseBluePart 43093Element 4309323 or 4206482×2
Technic Pin 1/2 with FrictionDark Bluish GrayPart 89678Element 63956351 spare in the box×2
Animal / Creature Body Parts
3 pieces
Creature Body Part, Barb Large (Claw, Talon) with ClipBright GreenPart 16770Element 6254271 or 6177124×3
Tiles Special
3 pieces
Tile Special 1 x 1 with Clip with Rounded EdgesReddish BrownPart 15712Element 6348057 or 6071274×3
Windscreens and Fuselage
3 pieces
Windscreen 6 x 4 x 1 Hexagonal with HandleGreenPart 27262Element 6513953 or 6341913×3
Pneumatics
2 pieces
Pneumatic Hose Connector with Axle ConnectorDark BrownPart 99021Element 6265670 or 6167942×2
Bricks Curved
1 piece
Brick Curved 2 x 1 No Studs [1/2 Bow]Reddish BrownPart 11477Element 6069984×1
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.