For the most part, you can go along just fine with your Mac not knowing its serial number or revision (manufacture year). You can still install programs, log in to the Apple Store, use iMessage with your friends and colleagues, and so on. However, problems may surface over time wherein some services such as iMessage or FaceTime will no longer allow you to log in.
The sample screenshot below shows that the Mac’s Serial Number indicates “Unavailable” which means the Mac has somewhat forgot its serial number for some unknown reason.
However, here are some VERY IMPORTANT reminders you should know before trying to fix this issue on your Mac’s serial number:
Search for Your Serial Number
Upon purchase of your Mac from Apple.com, you’ll get a receipt via email where your device’s serial number is indicated. The box where your Mac came in also has the serial number, which can be found on the card inside the box. Also, the Mac itself has its serial number printed on it. So there’s very little excuse not to have the serial number information of your Mac.
Provide a USB Flash Drive
As part of this procedure, you’ll need to be able to boot off a seconday drive, in which a USB drive is advisable to use. Don’t worry about getting a USB drive with a large storage space since the files are very small in size.
Get the Software
The software to be used is called Blank Board Serializer. The link for this software will not be provided therefore, search it online at your own risk.
After you have understood the risks and have prepared the necessary items to be used, you may now proceed with the steps below:
STEP 1: Format the USB drive with Disk Utility with the FAT filesystem.
STEP 2: Next, unpack the Blank Board Serializer program to your USB drive.
STEP 3: Using the Disk Utility, Restore the unpacked dmg file to your USB drive.
STEP 4: Click Done.
STEP 5: Shut down your Mac.
STEP 6: Reboot your Mac while holding the [option] key.
STEP 7: When presented with various boot devices, choose the EFI USB key.
STEP 8: On the usage agreement, click Accept to proceed.
NOTE: Take note of the warnings mentioned above once more. The next step is very crucial, which means take extra caution in performing it.
STEP 9: Enter your Mac’s serial number WITHOUT ERROR.
NOTE: Be mindful that zeros (0) and O’s look very similar.
STEP 10: Hit [Enter] when you’re done.
STEP 11: Click Yes on each following prompt.
STEP 12: Click Proceed.
STEP 13: Click Restart.
This completes the risky method of reviving your Mac’s serial number. You may go back to the Overview screen to check if the serial number is now showing correctly as shown below.