Explanations for these errors fall into two general categories: Lack of space of the backup disc, and problems with packet writing software.

The first case, lack of space on the disc, is caused by trying to back up large files without enabling the option to compress and split large files across multiple backup discs. If a file is not compressed, and it will not fit in the remaining space on the backup disc, then the software will ask for another disc and it will place the entire file on the new disc. If the file will not fit on the *NEW* disc either, generally because the file is larger than the capacity of the CD-R or CD-RW media, then you get this error. The only solution is to enable compression and splitting for files of a suitable size in the backup plan. In general, it is best to enable compression and splitting for files in excess of 10MB or so. It is usually unrealistic for other software to directly read such files from the backup disc, so there is no penalty for compressing them on the backup, and if you don't compress large files you increase the likelihood of wasting space on the backup because it ran out of space trying to back up a large file and had to leave a big chunk of space unused.

The second case, problems with the packet writing software, is a result of the frequently misleading or downright inexplicable error messages that can result if you don't have packet writing software properly set up for your CD-RW drive. It sometimes gives "Disk Full" errors because standard CD-ROM's appear to Windows to have no extra space - they are exactly full all the time. Without packet writing software, CD-R and CD-RW media may sometimes be mistaken for standard CD-ROM media. Please refer to the help text on packet writing software, and inability to write to the CD-RW drive.