How to resolve the error: This Disk Doesn't Use GUID Partition Table Scheme

If your SSD is currently attached via an external enclosure, you can fix this problem by following these steps:

1. Press command and space to open spotlight, then start typing Disk Utility, then choose the Disk Utility app. 
2. Once Disk Utility is open, you may see a message telling you that the SSD cannot be read by the computer.
3. Click on the Initialise button that appears in the message and your SSD will be visible in Disk Utility. 
4. Click 'show all devices' on the top left
5. Highlight your SSD (the very top option) and click the Erase button.
6. Type in a name for the new partition (this where you’ll save data on the drive and it’ll be the name for your SSD).
7. On the menu settings, verify that the partition is set to GUID Partition Table.
8. Verify that the selected format defaults to Mac OS Extended (Journaled).
9. Select Erase. The drive will now be partitioned, formatted, and ready for use.

If you have already installed your SSD in the machine and are getting this error when you try to restore from a Time Machine backup, then see this article for a fix.