Ask Different is a question and answer site for power users of Apple hardware and software. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I have seagate external portable hard-drive 1 TB, and I will be using with following Mac's.

13" White MacBook (Intel Core 2 Duo) running Snow Leopard 13" MacBook Air (Intel Core i5) running Lion iMac running Lion

What partition map I should use, GUID or Apple when formatting external portable hard-drive?

share|improve this question

GUID (or more properly GPT - the GUID partition table scheme) is the new bootable standard for Macs so use it unless you have macs that need to boot from this drive and cannot support GUID. APM is your only option in that unlikely case. The vast majority of macs will work with both in all instances - especially if you don't need it to be bootable.

APM is not widely supported on other OS - so that may also tip the scales to using GUID in many instances.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.