If your Mac has limited hard disk drive capacity, one of the first things that you might consider is adding an external storage. Typically, such devices are connected to your Mac with a USB cable, and they’re often quite lightweight (although larger capacity, heftier external drives models are also available).
The whole idea of an external hard disk drive is that it offers you additional storage that you can refer back to when needed but don’t require at all times. You might have some music files that you want to have to hand at all times, for instance, or you might be using a portable hard drive for storing recovery software or even a desktop profile.
External drives such as these are great and easy to use, requiring you to connect them by USB cable and power them on in order to read and write data, although they should always be ejected in the correct manner. This is a simple process: once recognized by your Mac, such a drive will appear as a mounted device, so all you need to do is drag this drive to Trash before disconnecting the USB cable and switching it off. You should always follow this process when removing USB storage devices in order to ensure that the device isn’t still reading or writing data when you remove it; interrupting the data cable while the drive is writing could lead to corruption.
However, you might be experiencing some problems with your Mac’s external or portable drive that are caused by other issues…
Image credit: Wikimedia Commons/Ysangkok
Faulty Drive or Cable?
One reason why you might experience an error message on your Mac while trying to access a portable hard drive is that the device isn’t working correctly. The cause of hardware issues such as this can be difficult to trace, but you should be able to spot them quite quickly.
For instance, your Mac might inform you that the device hasn’t been correctly ejected. If you haven’t attempted to eject the device then you can be pretty sure that there is a problem with the USB cable. Replacing this with a new cable should be your first step, although you might also check the external device with another computer to see what happens; your Mac may have a problem with the USB port or drivers.
Other problems and error messages might point to the presence of a serious hardware failure on your portable drive. In situations such as this you will need to turn your thoughts towards effective data recovery, as difficulty connecting to and reading the disk drive will only exacerbate the problem.
Various hard disk recovery tools for Apple computers are available; however, with a USB hard disk the process is likely to be slower than with an internal SATA device.
Resolving Error 0
Another common problem with Apple computers and external or portable hard disk drives is Error 0.
This is an “unidentified error” and often occurs whenever you attempt to transfer files that are too big for your Mac to handle.
For instance, you might have a video file several gigabytes in size that you are trying to copy to or from your portable device. It might be that you need to find another means of copy the file (perhaps burning it to disc) or break the data down using a file splitting utility.
Various satellite issues can make matters worse. For instance, if you are copying data to an external device formatted with the Microsoft FAT32 structure, you will be unable to add any file larger than 4 GB.
Additionally, container formats can cause further problems. It isn’t unheard of to be able to move a 40 GB .iMovieProject file to a portable hard disk and then be unable to copy a smaller file – all due to the fact that the larger file is in fact made up of many smaller ones.
In some cases, rebooting your Mac may be an option, but in the majority of cases either split the file (using a tool such as www.hjsplit.org) or format the disk drive (using the Mac Disk Utility) for exclusive use with your Mac or in NTFS format, thereby allowing you to copy larger files to it and avoid the dreaded Error 0!
Could a File Splitter Help?
While hardware and cabling issues might cause you a particular headache, the real problem with copying data to external disk drives on Mac OS X is the size of the data.
Circumventing this issue with a file splitter is probably the best option, particularly if you maintain a considerable amount of data on the drive already. If you are able to remove the data from the archive, however, then reformatting with one of the Mac file systems or NTFS should be your priority.
Author's own experience.