This how-to shows you the steps using Disk Utility 13 in OS X 10.10 Yosemite, but the process is the same if you’re using OS X 10.9 Mavericks or 10.8 Mountain Lion. Sometimes you want to wipe out all the data that’s on a hard drive or solid-state drive—erase it and start over. The best way to do this is to format the drive, which both erases the drive and prepares it for storing data by mapping out bad sectors, creating address tables for locating the data on the disk, and more. Similarly, you may have purchased a new drive that was formatted for Windows out of the box. You'll want to reformat that drive for your Mac. But formatting a drive so that it can be used as your Mac’s startup drive requires a slightly different procedure than formatting it for use as a secondary drive for storing data. Click the Erase tab if it’s not already selected.

At the bottom of the window, you’ll see some information about the drive you have selected. Look at the Partition Map Scheme entry. If it says GUID Partition Table, you can format the drive by selecting Mac OS X Extended (Journaled) in the Format pop-up menu, giving the drive a name, and then clicking Erase. (Remember: This erases everything on the drive!) You can now skip directly to Step 8. If the Partition Map Scheme says Master Boot Record or Apple Partition Map, you need to continue to step 5.

Once the drive is formatted it will be compatible to be read and written to on both a Mac and PC, and the resulting FAT file system is compatible with all versions of Mac OS X, Windows 95, 98, Windows XP, Vista, 7, Windows 8, even Windows 10, it’s one of the most widely recognized and usable file system formats.

Advertisement Now that every Apple laptop ships with a solid state drive, many of us are learning to live with smaller storage capacities once more. At the same time, external hard drives are cheaper and roomier than ever – which means there’s often plenty of room for backups and file storage on the same drive. Everyone should As the developer here at MakeUseOf and as someone who earns their entire income from working online, it's fair to say my computer and data are quite important. They’re set up perfectly for productivity with., and ideally Laptops, desktops and tablets are ultimately trivial items that can be replaced and hold little value, but the same might not be true of the data they contain. Losing a project you’ve worked years on. If your Mac’s hard drive is small but your Time Machine hard drive is big, it might be worth using the drive for both backup and storage purposes. How Time Machine Works Typical external hard drive sizes have swelled to over a terabyte (1000 gigabytes), but many new MacBooks only come with 128 or 256 gigabytes of storage.

Time Machine relies on historic backups, which means that older versions of files and items you remove are stored until a point in time when the space is required again for newer data. For this reason the more space you give Time Machine, the more space it will use.

You might not care about having extensive backups of files you deleted years ago. You might download a lot of video or other large files before moving them to external locations, and that means much of the space occupied by your Time Machine disk could be put to better use. If you only ever need an up-to-date backup of your Mac, then you too could put that gigantic hard drive to better use. It must be said that the more you use a mechanical item, the more likely it is to fail. Hard drives have mechanical, moving parts so they do occasionally die horrible, crunchy deaths. Using your Time Machine backup as an external drive may shorten the life of your drive, as you will wear out the various moving parts quicker by performing more read and write cycles.