Have you ever encountered the Error code 0 in your finder when you are trying to copy large files from your Mac to an external drive? The Error code 0 usually comes with this message: “The operation cannot be completed because an unexpected error occurred.” This sounds rather ominous, but the cause of the problem may be quite simple, so don’t get instantly worried.
First of all, most external drives including USB flash drives are formatted using the FAT or FAT32 file system, which is a file system specifically used for Windows. Rigt now, Windows uses the NTFS file system, but before NTFS, there was FAT or FAT32. This file system is compatible with Mac OS X and Linux, enabling Mac and Linux users to read and write data, so several external drives still use it until now. They cannot use NTFS because Mac and Linux systems can only read but not write data on NTFS drives.
Unfortunately, even with its compatibility with different platforms, the FAT32 file system is quite outdated. One limitation it has is its 4GB file size limit. This is the main reason why the Error code 0 appears, usually or more likely when the files you are copying are quite large and are beyond 4GB. So what can you do?
Your first option is to try and make the file smaller. Since there is such a restriction, an individual file should be no larger than 4GB, even if your external drive is. This means that if you have an exceptionally large file, you will have to use file compression systems such as zip, rar, and dmg (or creating a disk image).
Your second option is to reformat the external drive or USB drive using Mac OS X’s file system, which is HFS+. This will get rid of the 4GB limitation, allowing you to copy files of any size provided that it fits the overall capacity of your external drive.