When you use Ntbackup to back up to a file on a FAT or FAT32 file system, you may receive:

\[Insert media\]
The fixed media is full. You cannot back up all of the specified data to this disk device.
The backup operation will stop.

The maximum size of a file on a FAT or FAT32 partition is limited to 4 GB (4,294,967,296 bytes). The .bkf file has attempted to exceed this limit.

To workaround this issue, do any of the following:

- Convert to NTFS using the Convert <Drive:> /FS=NTFS command.

- Locate the .bkf file on an existing NTFS partition.

- Reduce the size of the backup.

NOTE: Always review the backup log and Application event log after you perform an unattended back up.

NOTE: The maximum size of a file on an NTFS partition is 16 exabytes.