When I erase my SSD in Disk Utility on my Mac, I see three options: GUID Partition Map, Master Boot Record, and Apple Partition Map. I know about GUID and MBR as some of my hard drives are formatted with them. Only for Apple Partition Map, I know nothing. What is Apple Partition Map and how about GUID vs. Apple Partition Map? I’m new to Mac. Can anyone tell me the best partition map for Mac?
Hey, I’m glad to answer your question “What is Apple Partition Map?”. Apple Partition Map (APM) is an old partition scheme that was originally designed to manage disk partitions in Mac OS 9 and early versions of macOS (Mac OS X).
It was primarily used on PowerPC-based Macs and was the standard partition map before Apple transitioned to the modern GUID Partition Table (GPT) with the introduction of Intel-based Macs in 2006.
Although GUID Partition Map far outperforms Apple Partition Map, Apple Partition Map is still used in external drives or removable media like CDs and DVDs for booting PowerPC-based Mac systems. It is still readable and writable on Intel Macs, but AMP is not used as a default or supported for booting modern macOS versions.
GUID Partition Map (GPT) and Apple Partition Map are two available scheme options in Disk Utility. I’ve listed their differences below for your reference.
Usage: Apple Partition Map is used primarily for PowerPC-based Macs running Mac OS 9 or early versions of Mac OS X. GUID Partition Map is used on all modern Macs, particularly those running macOS 10.4 (Tiger) and later, and required for Intel-based and Apple Silicon Macs.
OS Compatibility: AMP only works with PowerPC Macs (older Mac systems before the Intel transition). GPT is compatible with modern Macs, Windows PCs, and Linux machines.
Partition limitations: Apple Partition Map is limited to 16 partitions and is mainly used on smaller and older hard drives. GUID Partition Map allows up to 128 partitions in macOS.
Learn more about Apple Partition Map vs. GUID Partition Map.
When talking about the difference between GUID Partition Map and Apple Partition Map, I briefly say that if you have a modern Mac, choose GUID when erasing.
In Disk Utility, APM is still available as a scheme option for drives, but it is especially for older Mac models or systems that specifically require APM. If you partition a disk for modern Mac usage and take compatibility with Windows or Linux into account, the recommended partition scheme is GUID Partition Table (GPT).
The best partition map for Mac is the GUID Partition Map. It is the modern partitioning map for modern operating systems and hard disks. It is also compatible with Windows and Linux.
The other two partition schemes are for older system versions and disks. So, don’t be confused with them, just go ahead to select GUID when formatting a hard drive.