Keep in mind that Mac OS X can handle files up to 16 terabytes, but only on HFS+ file systems. Other formats have a much lower maximum size, and that’s most likely the reason why you’ll get the 1309 error code when you try to move them. If you get this error while trying to move a file from your mac to an external drive, you are likely seeing this error code because the external drive is formatted to the Fat32 file system which only supports a maximum file size of 4 GB. If the file exceeds that, you will get this error every time you attempt to move it (unless you do something about it). Fortunately, there are ways around this error, and not all of them will require you to be technical. Below you will find two verified methods that will help you fix this error:
1. Split the big file into smaller files
If you don’t have the option to reformat the external drive, splitting the file into two smaller files is arguably the only what that will allow you to complete the file transfer without seeing the 1309 error. Note: If the external drive was previously used on a Windows computer, chances are it’s formatted to Fat32 which only allows a maximum File Size of 4 GB. In case the file you’re trying to move is bigger than this, you can get around this problem by splitting it into sections before moving and restoring it back to its original size. The easiest way to do this is via the Terminal app, but this will require you to get a bit technical. If you prefer a simpler GUI approach, our recommendation is to use WinRar or WinZip to split the files before initiating the transfer again.
1.1. Split files via the Terminal app
macOS has a special Unix command specifically for scenarios where you need to seamlessly split and re-unite a file. Note: This command will work on every macOS version as long as you run it from the Terminal App with the required permissions. Here’s how to split a big file into smaller files via the Terminal app and avoid the 1309 error:
1.2. Split files via WinRar or WinZip
If you don’t want to get involved with the technical approach, you can simply use WinRar or WinZip to split the big file into multiple compressed archives before you move it and merge it again. Here’s a quick guide on how to use the WinRar or WinZip to split files and avoid the 1309 error:
2. Change file system to MacOS Extended (Journaled)
If the external drive that throws the 1309 error when you transfer files to it is empty or it contains files that you can delete, the quickest and painless way to avoid the error entirely is to change the file system to Mac OS Extended (Journaled). This fix is ideal in situations where the drive is formatted with Fat32 and the file you’re trying to transfer exceeds 4 GB. Here’s a quick guide on formatting the external drive to the macOS Extended file system:
