Microsoft Backup Err Msg: Alert! Unknown Compression of File (101559)

The information in this article applies to:
    Microsoft MS-DOS operating system 6.0
    Microsoft MS-DOS operating system 6.22

This article was previously published under Q101559


When you try to restore backups with Microsoft Backup for MS-DOS or Microsoft Backup for Windows, you receive the following error message:

Alert! Unknown compression of file


This error occurs when:
    The backups were made with a beta version of Microsoft Backup. -or-

    You used MS-DOS 6.22 to create a compressed backup and then attempted to restore it using Microsoft Backup for MS-DOS 6.0.


If you made backups with a beta version of Microsoft Backup, there is no workaround for this situation. You must create new backups with the final release version of MS-DOS 6.0 or later.

If you made backups under MS-DOS 6.22 Backup with compression turned on, either restore the data with MS-DOS 6.22 version of Backup, or back up the data with compression turned off.

Modification Type: Major Last Reviewed: 11/19/1999
Keywords: KB101559