The GUID Partition Table (GPT) replaces the previous master boot record (MBR). GPT partitions can hold 18 exabytes compared to 2.2TB for the MBR.

Now with a little bit of searching I've found a Windows based tool that claims it can recover a GUID partition table called Partition Guru Professional Edition (the free version does not handle ...

We need to ensure that the partition style is a GUID Partition Table (GPT) or a Master Boot Record (MBR). For that, run list disk. Check if the “Gpt” column contains an asterisk (*).

What actually happens is that it interprets the GPT partition table incorrectly, and that causes it to get confused about what is where on the disk.

2] Convert drive to GPT MBR (Master Boot Record) and GPT (GUID Partition Table) are two different ways of storing the partitioning information on a drive.

Note that this command works only on Intel Macs with hard disks formatted using the GPT (GUID Partition Table) format with a journaled Hierarchical File System Plus (HFS+) file system.