How Should You Format An External Drive For a Mac?

When you buy a new external drive for your Mac, it is not going to be formatted for your Mac. You should use Disk Utility to set the drive up right before using it.

Comments: 18 Responses to “How Should You Format An External Drive For a Mac?”

    Russell Tolman
    8 months ago

    hi, thanks for all the info on formatting drives. Just wondering if you have any insight into why Time Machine sets up the drives as Case Sensitive? thanks. I was just wondering.

    8 months ago

    Russell: I suppose it covers all bases. What if you add an external drive at some point that is case sensitive, but you formatted the Time Machine drive as not? So with case sensitive, it can handle both ways.

    Joyce Hann
    8 months ago

    Hi, As I have sent high capacity thumb drives to family to share digitized home movies (128 gb) I was careful to use exfat. The caution about the old Mac format being limited to 32 gb made me wonder if there was some limit in exfat. Few of my cousins could get the 128 gb drive to mount and given some low tech users managed to erase instead.

    FYI, I uploaded to YouTube and shared from there instead. Movies were from the 1950s and on.

    Linda Lyn
    8 months ago

    Thank Gary
    Very good, Very useful very clear thank you again đź‘Ť

    Jonathan
    8 months ago

    Does running Disk Utility in nonSafe Mode do the exact same thing as running it in Safe Mode?

    8 months ago

    Jonathan: Safe mode boots without any system extensions and launch items. So if one of those would be getting in the way of Disk Utility I suppose it would be different, but I'm not sure that is an issue. What are DOING with Disk Utility that Safe Mode is involved?

    Michael
    8 months ago

    Thanks Gary. Really helpful and timely tutorial. I am currently searching for a new 1TB external drive. I wondered if you have a "preferred hardware" list I could use to help my purchasing decision? Regards Mick UK

    Fred Cippele
    8 months ago

    Gary, I'm currently using a disk through Time Machine for backup on my 2018 MacBook Air. It's using the Mac OS Extended (Journaled) format. I'm moving over to the Mac mini M2 next week. Will it automatically move to APFS, or will I have to erase/reformat per the video to take advantage of the increased speed on APFS. Thanks.

    8 months ago

    Fred: It shouldn't reformat. I don't think you'll notice any speed difference.

    Michael
    8 months ago

    Thanks for your response Gary. I should have been more specific, I am looking for a sad not a hhd. I think it would be better when travelling. The Samsung T7 Touch looks quite good. A supplementary question please. I use an Apple Time Machine but intend to use the SSD as a secondary back up for key data. Do you use back up software or do you just use copy and paste? If software, do you use 'incremental back-ups" Thanks Michael

    8 months ago

    Michael: I use Backblaze as my secondary backup. This way I have a backup that is not in the same location as the computer and the Time Machine backup in case of a disaster or theft. If I wanted to have a second local backup I would just use a second Time Machine drive.

    Louis Martin
    8 months ago

    Can you partition an ext. drive of 1TB to have a part. A of 256 GB as a Time Machine for my basic Mac mini M1 and a partition B of a clone of OS Ventura that I can start with even if I presume it will be slower than the int. drive and a extra partition C ? I have done this on my MacPro 2010 on internal partitioned SSD's and updating the cloned OS to see how it works and if every thing works, updating the main OS and working for there. With a new OS, I would update the cloned OS and so on. Thanks

    8 months ago

    Louis: I don't recommend it. Give your Time Machien drive as much space as possible. 1TB is already very tiny for a Time Machine drive. And what's the purpose of the bootable partition? Do you think you'd really end up in a situation where you'd need it? Would you really work from a slower external boot disk for a while instead of just getting things fixed? I gave up wasting time creating and updating external boot drives like that more than 15 years ago. Thing of the past unless you work in a missile silo or something.

    Jasper
    8 months ago

    I’d read on Carbon Copy Cloner’s web instructions that APFS is optimised for SSD and not recommended for HDD. I use Carbon Copy Cloner to back up to an external HDD, which is APFS formatted and works, although I’d had a few error messages about Snapshots. I don’t really understand what they are and have turned-off having them backed up (all seems well). Does this all sound sensible? Should we be using HFS for HDDs?

    8 months ago

    Jasper: You don't need to backup your Snapshots. You can use APFS for your external HDD just fine.

    Carole
    7 months ago

    I purchased a used iMac 2008 and have been using it for a number of years. It was connected to 2 Seagate backup plus (8T) using Time Machine. iMac crashed in December 22. I purchased a 2012 Mac mini (Catalina) but some files and photos say “Permission not granted”on HD’s external drives. I tried to reset permission, but now I cannot use my Macmini, as It is not recognized as my default computer. I can see files but but it is dimmed and cannot change documents. I am in a real predicament.

    7 months ago

    Carole: You have a lot going on there with a very old Mac mini (did you wipe it before use?) and permissions issues. I'd get an expert to take a firsthand look.

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