Copy Error Code 0 : What it Means in Mac OS X
“The operation can’t be completed because an unexpected error occured (error code 0).”
You’re likely to see this error when you are attempting to copy files to an external hard drive that is formatted as FAT. FAT32 is a Windows file system that can be read and written to by Mac OS X. The problem with FAT32 format is that they can not hold file sizes larger than 4GB, so if you are trying to copy a file that is larger than 4GB to a FAT32 formatted drive you will immediately be presented with the ‘error code 0’ message.
The simplest solution is to use drives formatted with Mac OS Extended (Journaled) or HFS+ file systems, however a Windows PC will not be able to access either of these file systems without additional software. There is no reliable way to force FAT32 to accept file sizes larger than 4GB, and FAT16 is an even older file system with worse limitations of 2GB file sizes.
Do note that if you want a drive to be properly accessible by both Mac OS X and Windows, you can format the drive as NTFS, and use an NTFS mounter for Mac OS X to try and write to the drive, however NTFS is not officially supported by Apple and you may run into some problems when writing data to the destination device.
You’re much better off using a FAT file system if you want true Mac and Windows compatibility with a drive, and as long as you avoid enormous files or copy them directly between a Mac and PC – and not the intermediary disk drive – you won’t see those Error Code 0 messages in the Finder when trying to copy anything.