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 Open StudBlackPart 85861Element 6168646 or 61006271 spare in the box×2
Technic Bricks
2 pieces
Technic Brick 1 x 1 with Pin HoleBlackPart 6541Element 654126×2
Tiles Special
2 pieces
Tile 1 x 2 with Stud Notch LeftTrans-RedPart 5091Element 6510128 or 6477746×1
Tile 1 x 2 with Stud Notch RightTrans-RedPart 5092Element 6510142 or 6477752×1
Minifig Shields, Weapons, & Tools
1 piece
Weapon Spike Flexible 3.5LBlackPart 64727Element 6270085 or 6173917×1
Stickers
1 piece
Sticker Sheet for Set 42212-1[No Color/Any Color]Part 10110656Element 6522708×1
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.