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.
Pneumatic T-Piece (T Bar) [New Style]BlackPart 4697bElement 61042091 spare in the box×1
Pneumatic T-Piece (T Bar) [New Style]Light Bluish GrayPart 4697bElement 42115081 spare in the box×4
Tiles
4 pieces
Tile 1 x 1 with GrooveLight NougatPart 3070bElement 6480394 or 60783991 spare in the box×4
Animals / Creatures
3 pieces
Animal, FrogWhitePart 33320Element 6550163 or 6298930×3
Bricks Special
1 piece
Brick Special 1 x 1 Studs on 4 SidesReddish BrownPart 4733Element 6133765 or 4528447×1
Technic Beams
1 piece
Technic Beam 1 x 2 Thick with Pin Hole and Axle HoleBlackPart 60483Element 6265091 or 6006140×1
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.