Mac OS X: "Error in user parameter list (-50)" With MS DOS-Formatted Volume

This document explains what to do if the alert "Error in user parameter list (-50)" appears when working with an MS-DOS-formatted volume.
This article has been archived and is no longer updated by Apple.

An alert appears that states:
    "Error in user parameter list (-50)" (minus 50)

The message may also include the name of a file you are using or copying.

This happens when copying a file to an MS-DOS-formatted disk or modifying a file on the disk.


Note: You can verify that the volume is formatted as a MS-DOS disk by selecting its icon in the Finder and choosing File > Get Info.

A file cannot be copied

Certain characters that can be used in a Mac OS X filename are not allowed in MS-DOS filenames. This can prevent the file from being copied, and can
occur when a filename contains non-printing ACSII characters, or any of these characters:

? / \\ < > " | > *

Remove these characters from the names of the files before you copy.

Alternatively, for a longer-term solution, reformat the volume as Mac OS Extended (HFS Plus). Be sure that any important data on the volume has been backed up first (after renaming any files with characters mentioned above), and that any other computer you will use the volume with works with Mac OS Extended format disks.

A file cannot be modified

If the alert appears when you try to change a file, try copying it to the computer's hard disk first, then copying it back when you are finished.

Alternatively, consider formatting the volume as Mac OS Extended as described above.

Related documents

107032: "Mac OS X 10.2: 'Error -43' When Copying Files to Windows Shared Volume"

Last Modified: Feb 17, 2012

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