All you need to know about configuring an external hard disk in OS X

At the present time, cloud storage technologies are used almost everywhere. The cloud is fast, convenient and most important, always at hand. However, without physical storage, we still can not do. Hard disks and SSDs are used as system disks, and ordinary flash drives are still in the process. Some drives are ready to work immediately out of the box, others need to be formatted; In addition, the bundle comes with proprietary utilities that the manufacturer recommends using. In this article, you will learn how to properly prepare an external drive to work in OS X.

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When you first connect an external drive to the Mac, it will automatically be mounted and ready for use. However, before you rely on it, it’s worth checking out a few important things.

Note. I do not have a disk over which to mock, so I will show everything using the example of an old USB flash drive, but do not worry, in the case of a hard disk, the setup procedure will be similar.

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The first thing to consider is that most likely your new disk will be formatted in FAT32, instead of the most common extended and ntfs (for Mac and Windows, respectively). FAT32 is good because it has support for both reads and writes in both operating systems. This is the easiest way, if you need a universal disk, although it has some limitations.

First, FAT32 does not support logging, which would help prevent data corruption. Secondly, it does not support the assignment of file system permissions. In addition, FAT32 disks usually have an MBR partition scheme that does not work with Apple CoreStorage, and therefore will not allow the use of data encryption on the disk. Third, the FAT32 limitation on the file size is 4GB, which is very, very bad by modern standards.


Sometimes a special software is included in the disk drive package, with which you can make disk layout and create backup copies of data. It can be convenient, but I still would not recommend using it, because OS X has all the tools it needs. Third-party disk management tools can cause compatibility problems that will lead to data loss.

If you are going to use your external drive only with your own or other Mac computers, it’s best to format it in the extended-format that is used in OS X by default. If there is a need to connect to Windows-machines, then uniquely use FAT32.

Disk layout

For all manipulations with drives, OS X uses Disk Utility, which is in the folder Programs – Utilities. Well, let’s run it and proceed to markup our external drive.

Step 1. Select the disk and the number of partitions

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Select our disk in the sidebar on the left and specify the partition table. If you need several volumes, specify their number in the drop-down menu Section layout or using the button +, if there is an unallocated area on the disk.

hint. If you select a disk in the sidebar, the Disk Utility will display all its partitions. For your primary drive, they will be gray, because you can not format or change the partition table for the boot disk. For all other connected devices, these options will be available.

Step 2. We specify the scheme of sections

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The default is usually the GUID partition scheme, but it’s best to open Options and check that this is really so. And anyway, with any operations with the disc, the proverb “Seven times measure – once cut” is more relevant than ever, especially if the disc already contains any data.

Step 3. Check and confirm all changes


After you check all the settings, the last thing to do is to apply them. Click the appropriate one and wait for the end of the process of breaking our disk.

As soon as the changes take effect, the disk will be ejected and re-mounted to your Mac’s file system. Now he is completely ready to work.

Something else

If you want to go further, you can test the drive to make sure there are no bad sectors and other errors. To do this, you can use third-party applications, such as Drive Genius or Tech Tool Pro, because Disk Utility does not have this functionality. But still there is one trick that will help to check disk errors with it. This method is based on Safely Erasing a Disk. As you probably know, this erasure is done by writing each sector with zeros, thereby letting us know if there are bad sectors, if the operation fails.


It’s worth noting that the safe erasure procedure and other similar hard disk operations that check each sector of the disk take a long time (several hours).

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I wish all your disks trouble-free work, let them work quickly and please you, dear readers. If you have any questions about setting up an external hard drive in a Mac – ask them in the comments.