Macintosh Files on MS-DOS Disks May Not Work

This article was previously published under Q101895

Copying a Macintosh file from a Windows NT Advanced Server computer onto an MS-DOS floppy disk may render that Macintosh file unusable.

Macintosh files have two pieces, referred to as the data fork and the resource fork. NTFS keeps track of both of these forks, thus allowing Macintosh files to reside undamaged on an NTFS volume.

The standard method for putting Macintosh files on FAT disks is to split the Macintosh file into its two pieces when the file is copied to the FAT disk. The two pieces are then put back together when copied back onto a Macintosh. Because Windows NT Advanced Server Services for the Macintosh requires an NTFS partition, Windows NT Advanced Server does not need to split the two forks.

When a Macintosh file is copied from a Windows NT Advanced Server computer to a FAT disk, the copied file loses the extended attribute that consisted of the resource fork. When this Macintosh file is used, it may not work if the Macintosh file needed the resource fork. (As is the case with an application.)