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USB Storage Drive not detected or “Device Not Correctly Connected” message for MacOS®

If your USB storage drive is not being recognized by applications on your Mac, you may be able to fix this by reformatting the drive and ensuring the scheme is set as Master Boot Record (MBR).

To do this, simply follow the steps below. Please note, formatting your drive will delete all of the data it contains. If the drive you're formatting contains any files you need to keep, be sure to back up the information before proceeding.

  1. Launch Disk Utility. This can be located by opening Finder and then selecting "Applications, then "Utilities." Then,  select "Disk Utility."
  2. Disk Utility will then open in a single window divided into two panes with a toolbar across the top. The left-hand pane contains the drive(s) and any volumes associated with the drives in a hierarchical view.
  3. Select the storage device that you wish to format from the left-hand pane. Be sure to select the drive in question. Drives usually have names that refer to the drive manufacturer or an external enclosure manufacturer.
  4. The selected drive will appear in the right-hand pane with details about it, such as location, how it’s connected, and the partition map in use.
  5. With the drive selected, click the "Erase" button at the top of the screen.
  6. When the window opens, you will be given the option to rename the drive.
  7. Set the format option to "exFAT."
  8. Set the scheme to "GUID Partition Table" (GPT,) unless an older application requires you use MBR.
  9. Click the "Erase" button at the bottom of the screen. Once complete, your drive will be formatted.

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