Mac: External hard drive is not recognized - what to do?

In this practical tip, we will show you what you can do if your external hard drive is not recognized on the Mac.

External hard drive is not recognized on the Mac - so you solve the problem

Connect your external hard drive to your Mac using a USB cable:

1. Usually, the hard drive should appear in the Finder under "Devices". Click on your hard drive there.
2. If nothing is displayed there, open the "Hard Disk Utility" using the "Finder" under "Programs". Check if your hard drive is shown here on the left.
3. If it is displayed there, right-click on the displayed hard disk and select "Open hard disk".
4. Maybe your hard drive is also deactivated. Then right-click on the external hard drive and select "Activate hard drive".
5. If your hard disk is not shown here either, check whether the hard disk has sufficient power. Some 2.5-inch hard drives have to be connected with two USB plugs. Alternatively, a power supply can often be used.

Mac: Format check of the external hard drive

If your hard drive is still not recognized, the format of the hard drive could be the reason:

1. Check the format of the external hard drive. If it is displayed in a Windows system, you can determine this directly under "Computer". If no format is displayed here, right-click on the hard disk and look for the information under "Properties".
2. If your hard drive is formatted according to the Windows NT file system (NTFS), it could not be recognized by the Mac. You can then format your hard drive in "FAT32" format. In the following practical tips, we will explain how to format the hard drive under Windows 8, Windows 7 or Windows XP. Be sure to back up all data beforehand. These are lost when formatting.

Also read how to format a hard drive without an operating system.