Sometimes, you’ll come across an external hard drive which doesn’t actually say ‘compatible with Mac’ on the box. But that doesn’t necessarily mean its not supported, it just means it will not work out-of-the-box. You just need to spend a few minutes formatting it to a Mac-compatible format, set it up for Time Machine and you’re good to go. I’ll tell you exactly how to do that. You can watch the video below for a step-by-step guide or carry on reading.
Back up any files on the external hard drive before you format it
First, connect your external hard drive to your Mac. Then you need to go to Disk Utility; you can find that under the Utilities folder, within Applications. Double click to open it and you should see your external hard drive on the left hand side. Click on its name to enable the Erase button then click it. Make sure you’ve backed up any documents and media already on there if you’ve used it before you do this as this will wipe the drive! If it’s brand new, you can go ahead and give the drive a name. We want the OS X External (Journaled) format to make it Mac-compatible. Hit Erase and after 15 seconds your drive is ready to be used with your Mac. Well, almost.
Safely eject the drive from your Mac and then re-connect it. You can confirm its format by going into it, right-clicking and selecting Get Info. This will also show you what permissions you have. Read and Write is what you want as Read Only will not allow you to add files to the drive.
Setting up your external hard drive for Time Machine
Open up Time Machine by selecting the icon on the top right (next to the Bluetooth icon). Alternatively, hit CMD + Space bar and type ‘Time Machine’ in the search bar and hit enter to open it. Next, click on Enter Time Machine. You might get an error message pop up. That’s absolutely fine.
Go ahead and click ’Set up Time Machine’ and then choose your external hard drive as the back up disk. You can use multiple drives with Time Machine, so if you want to do that then click ‘Use Both’. If you only want to use the drive you just formatted then click ‘Replace’. You’ll then notice a count down until the next backup, it’ll start preparing and the back up will begin. Pretty simple eh? The next time you plug in your drive, Time Machine will work its magic or you can obviously choose to keep it plugged in but I prefer not to.