If KBACKUP cannot find a valid header on your backup medium, although you have written an archive to it using KBACKUP , than there is (hopefully) only one possible reason for this: you are using a tape device that rewinds after closing a file. KBACKUP requires you to specify a device that does not rewind on close. These devices often carry an ``n'' in their name. If you try using a device with rewind-on-close feature, KBACKUP will overwrite its header with the directory and afterwards overwrite the directory with the actual archive, instead of writing the files one after another.
In version 
, I have introduced an option to check a tape device for
compatibility with KBACKUP
and also autodetect the proper device file.