How do I make the first backup with ukopp

I am not able to make the first backup with ukopp after substituting the crashed hard disk. Please let me know what I should do. I used for years ukopp for backups, first of my Ubuntu 16 notebook and then, after update, for Ubuntu 18. One month ago the hard disk crashed and I am not able to backup with ukopp my new SSD running with Ubuntu 20. I am used to create the backup in an external USB disk. Now I want to keep the last backup of the crashed disk int he same USB disk and add the new backup of the new SSD.

MORE DETAILS thanks to Artur Meinild's invitation.

My STEP 1: edit job. I chose as the target the habitual USB disc Maxtor and the incremental verify, then I clicked the button Done.

Ukopp wrote (minosse is my home directory):

target directory is valid
new target: /media/minosse/Maxtor/
target: /media/minosse/Maxtor/
target directory is valid

My STEP 2: run job.

Ukopp wrote down one after the other different data and then, as usual, opened a new window with the message:

backup target /media/minosse/Maxtor/ 300703 files (30,7 GB) will be copied to (or deleted from) backup media

continue?

My STEP 3: I answered Yes.

Ukopp wrote:

begin backup
files: 300439 bytes: 30,6 GB
using backup directory: /media/minosse/Maxtor/
assign new version numbers to modified backup files and purge expired versions from backup location

Then Ukopp wrote down a list of files and after everyone the comment "not valid argument" ending with the lines:

too many errors, giving up
*** BACKUP FAILED

The STRANGEST THING to me is that the list contains exclusively files of the backups of the two older Ubuntu 16 and Ubuntu 18 hard disks, when I expected ukopp to create a new backup directory. For the Ubuntu 18 version almost every file was located at the end of a long directory series, with the the same 4 first directories for all the unvalid files:

home-Ubuntu18-210724/minosse/.cache/software-center/...

Sorry for repeating myself: what I want is to keep the last backup of the crashed disk int he same USB disk and to create beside the new backup of the new SSD with no relation with the old backups.

I found a solution of the problem, but I have lost the to old backups in the disc (not the data, I have other copies). The main passage was to correct the file names that caused the "not valid argument". I have also excluded from the backup job all the caches and thumbnails. Now I have the ukopp backup of the new SSD of the notebook in the disc and it is the main progress.