How to Transfer More Than 4GB on a Mac
By Jeff Grundy
Modern Mac computers use the HFS+ file format, which has a maximum file size limit of about eight billion gigabytes. Therefore, about the only time you cannot transfer files larger than 4GB on a Mac is when trying to copy data to an external hard drive formatted with the FAT32 file format. FAT32 has a file size limit of 4GB, and if you attempt to transfer a file larger than that, an error occurs. To overcome the 4GB size limitation, you must reformat the external drive using the HFS+ file format.
Connect the external drive's AC adapter if it has one and plug it into an electrical outlet. Connect the cable to the external drive and a free USB port on the Mac computer. Wait a few seconds for your Mac to detect the external drive and mount it automatically.
Click the "Finder" icon on the dock. Double-click the device name of the external hard drive in the Devices list. Press "Command-A" to select all of the files and folders on the external hard drive, and then press "Command-C" to copy them to the clipboard.
Click the system drive in the "Devices" list, and then select a folder in which to store the files from the external hard drive temporarily. Press "Command-V" to copy all of the files and folders from the external hard drive to the selected folder.
Click "Applications" in the Places list of the Finder window. Scroll down to and double-click "Utilities." Double-click "Disk Utility."
Select the external hard drive in the left navigation pane. Click the "Erase" tab, and then select "Mac OS Extended (Journaled)" in the "Format" drop-down list.
Click the "Erase" button, and then wait for OS X to reformat the drive with the new file system. Return to the Finder window, open the folder where you saved the files from the external hard drive and press "Command-A." Press "Command-X" to cut the files to the clipboard. Open the external hard drive in the Finder window, and then press "Command-C" to move the files and folders from the system drive to the external drive. After you reformat the external hard drive using the Mac OS Extended (Journaled) file format, you will no longer see errors when copying files larger than 4GB.
- After you reformat the external drive with the Mac OS Extended (Journaled) file system, you will no longer be able to view its contents with a Windows computer without special software. Applications such as MacDrive, HFSExplorer and Paragon HFS+ for Windows enable you to view Mac-formatted drives on a Windows machine (links in Resources).
Jeff Grundy has been writing computer-related articles and tutorials since 1995. Since that time, Grundy has written many guides to using various applications that are published on numerous how-to and tutorial sites. Born and raised in South Georgia, Grundy holds a Master of Science degree in mathematics from the Georgia Institute of Technology.