Here is how to reach someone who can check it:
- Microsoft Support chat or phone: Go to support.microsoft.com/contactus, choose Surface, and sign in with the account the device is registered to. Ask for a Surface hardware support agent and say you need the manufacturing date for the serial. Those agents can see build and warranty records that the public warranty checker doesn’t show.
- Microsoft Store or Answer Desk: Call or chat with them, or visit in person if one is near you. They can pull up the same records and sometimes give you the information in writing.
- Authorized service provider: If you’re dealing with a dealer or repair center, they can request the build date through Microsoft’s partner channel.