Apple - Do Macs store a serial number on the disk?

Apparently the only ways to find out a Mac's serial number (if you don't have the Mac physically present) are:

When you had the Mac, you:

• Registered it with Apple (check your support profile at apple.com)
• Ran and saved a copy of System Profiler's output

Without the Mac:

• Have a sales receipt from a retailer that puts the serial number on their receipts
• Purchased it from a retailer that keeps track of serial numbers
• Find the box the Mac came in

Thankfully, after I posted this question, the buyer was able to find the original box, which gave him the serial number.

But the actual answer to the question is: No, Macs do not normally store their serial number in a disk file.

The computer’s “Serial Number” is not stored in the software, but the hardware as far as I can remember (because there’s a method in the Cocoa SDK to read it).

You can also ask the OS to tell you the Serial Number by going to /Applications/Utilities/Terminal.app and executing:

ioreg -l | grep IOPlatformSerialNumber

This value, is stored in some form of nonvolatile memory on the motherboard, because you can wipe your hard drive completely clean, and the results will always be the same, until you have to change your board.

All that said, the vendor should have the serial number of the machine it sold, and Apple will know that the serial number went to X vendor. They have a decent control about that as far as I know.

So if you have the receipt from Amazon, then you can try contacting them about the issue.