Can't Copy to a New Drive On Mac

Have you tried to drag your files from your target drive to a new external drive only to have the icon bounce back at you and not copy?

You may be having problems copying files to a drive if:

You purchased a new external drive
You are using a drive that had previously been used with a Windows computer

The drive causing trouble may be formatted for Windows. A Mac computer can read a drive that has been formatted for Windows, but cannot write to that drive. To make a Windows-formatted drive read/writeable on a Mac, you will need to reformat the drive for Mac.

WARNING: Re-formatting the drive will delete ALL data that is currently on that drive. If there is currently valuable data on the drive, make sure that you have a good backup before proceeding.

1. Connect Your Drive - Remove all external devices except for the drive that is to be formatted. This will prevent the accidental format of the wrong device.

2. Open Disk Utility - Use macOS's Disk Utility app to format the drive. Locate Disk Utility in Applications > Utilities and open it.

3. Disk Utility’s left pane shows the storage devices connected to your Mac. Click View, top left, and select Show All Devices. Underneath each device are the drive’s partitions.

Select the device you want to format. Then click the Erase button at the top.

4. Name, Format & Scheme - A dialog box will appear. Enter a new name for the storage device.

Click the pop-up menu for Format and select one of the formats. The default selection is OS X Extended (Journaled).

There’s a third selection you need to make called Scheme. Select GUID Partition Map.

Click the Erase button when you’re ready to proceed. When this is done, the disk should unmount and then remount with the new format, and will be ready for use.

Mac OS X 10.10 or Older

To format the drive using OS X 10.10 or older, attach it to your system, open Disk Utility and then perform the following steps:

Remove all external devices except for the drive being formatted. This will prevent the accidental format of the wrong device.
Select the drive device in the list of devices. This will be the item above any storage volumes on the drive. This item in the menu may show the manufacturer name, media size and so on.
Choose the "Partition" tab that appears.
Select "1 Partition" from the drop-down menu (or more, if you have a specific need for more than one volume). When you select a new partition layout from the drop-down menu, each new partition will be formatted to Mac OS Extended (Journaled) by default, but be sure to double-check this by selecting each in the partition diagram and then choosing the format for it.
Click the Options button and ensure "GUID" is selected as the partition scheme.
Click Apply to save the changes.

When this is done, the disk should unmount and then remount with the new format. It should now be ready for use.

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