USB Flash Drive Disk is full error message
A Helpful hint when using USB Flash drives and OS X (or Windows XP for that matter).
Mac OS X may show a "Disk is full" error message when moving or copying files to the root level of a USB Flash drive (also referred to as jump drives or thumb drives), even though the Get Info window for the drive shows there is plenty of space on the drive. This error message is not restricted to OS X alone. A similar error is also generated in Windows.
The problem seems to be the MS-DOS filesystem (more exactly, the FAT filesystem) used by USB Flash drive makers.
There is a limit to the number of files that can be stored at the root level (i.e., not within a directory) on the USB Flash Drive.
On Mac OS X (10.3.9 is what I tested with) the error message the Finder displays is: "The operation cannot be completed because the disk is full."
I repeated the same experiment on Windows XP with the same results.
On Windows XP, I get the error message:
"Cannot copy <filename without extension>: The directory or file cannot be created."
Regardless of Operating System, what these two cryptic error messages are not telling you is how to resolve the fact that there is obviously more space on the drive, but you can't place more files on it.
The problem is that the root directory of the USB drive can only hold a limited number of files. If you create a folder at the top level of the drive, you can place MANY more files inside this new folder.
For example, on my Mac, I wasn't able to add more than 121 files to the top level of the USB Flash drive. If I created a folder on the drive, then I could drop more than 350 files onto the drive (and I never got the Disk is full error message).
On Windows XP, the limit was higher. I was able to copy 256 files onto the USB Flash drive before getting the error message. I don't know why the number of files I could copy to the root level of the drive was different between Windows XP and Mac OS X, but creating a folder at the root level and adding files to the folder worked the same.
Hope this helps someone. Please pass this message on to other users of USB thumb drives since the error messages from the Operating Systems don't tell you how to get around the issue.
Dave Paules
Mac OS X may show a "Disk is full" error message when moving or copying files to the root level of a USB Flash drive (also referred to as jump drives or thumb drives), even though the Get Info window for the drive shows there is plenty of space on the drive. This error message is not restricted to OS X alone. A similar error is also generated in Windows.
The problem seems to be the MS-DOS filesystem (more exactly, the FAT filesystem) used by USB Flash drive makers.
There is a limit to the number of files that can be stored at the root level (i.e., not within a directory) on the USB Flash Drive.
On Mac OS X (10.3.9 is what I tested with) the error message the Finder displays is: "The operation cannot be completed because the disk is full."
I repeated the same experiment on Windows XP with the same results.
On Windows XP, I get the error message:
"Cannot copy <filename without extension>: The directory or file cannot be created."
Regardless of Operating System, what these two cryptic error messages are not telling you is how to resolve the fact that there is obviously more space on the drive, but you can't place more files on it.
The problem is that the root directory of the USB drive can only hold a limited number of files. If you create a folder at the top level of the drive, you can place MANY more files inside this new folder.
For example, on my Mac, I wasn't able to add more than 121 files to the top level of the USB Flash drive. If I created a folder on the drive, then I could drop more than 350 files onto the drive (and I never got the Disk is full error message).
On Windows XP, the limit was higher. I was able to copy 256 files onto the USB Flash drive before getting the error message. I don't know why the number of files I could copy to the root level of the drive was different between Windows XP and Mac OS X, but creating a folder at the root level and adding files to the folder worked the same.
Hope this helps someone. Please pass this message on to other users of USB thumb drives since the error messages from the Operating Systems don't tell you how to get around the issue.
Dave Paules
