Not all W-2 forms have the same layout. Box d would be labeled "Control number." It could be anywhere on the form. But box d is optional. If your W-2 doesn't have a box d, just leave it blank in TurboTax.
If you are trying to import your W-2 and TurboTax is asking for the control number from box d, and it's not on your W-2, ask your employer about it. Some employers this year mistakenly told TurboTax to require the control number for security for importing, but then issued W-2 forms without a control number. If that is your situation, the simplest thing to do is just enter your W-2 manually. It only takes a couple of minutes, and it would be a lot faster and easier than trying to solve the problem of a missing box d.
