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.
Plate Round 1 x 1 with Solid StudBright GreenPart 6141Element 6109808×4
Dish 2 x 2 Inverted [Radar]Trans-Light BluePart 4740Element 6580378 or 6245307×1
Dish 3 x 3 Inverted [Radar]WhitePart 43898Element 4179580×1
Technic Pins
6 pieces
Technic Pin with Friction Ridges Lengthwise with No Center SlotsBlackPart 61332Element 6279875×6
Plates Special
5 pieces
Plate Special Round 2 x 2 with Center Stud (Jumper Plate)Dark Bluish GrayPart 18674Element 6115080×1
Plate Special Round 2 x 2 with Center Stud (Jumper Plate)Reddish BrownPart 18674Element 6102360×4
Bars, Ladders and Fences
3 pieces
Bar 6L with Stop RingReddish BrownPart 63965Element 6170468 or 6155727×2
Bar 4L (Lightsaber Blade / Wand)Trans-Light BluePart 30374Element 6507882 or 6170187×1
Bricks
2 pieces
Brick 2 x 2 CornerTanPart 2357Element 4124455 or 4112541×2
Panels
1 piece
Panel 1 x 6 x 7 with 2 Columns and ArchTanPart 40066Element 6273864×1
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.