|Hi A, am happy you have cured the problem.|
As a matter of interest, where are you based? I am in West London.
Your English is good, but I suspect not your first language,as I think you misunderstood my comments:-
How were the files created / written on the External Disk?
(which program or method was used, and which operating system)
It is good practice to 'Test Read' Backup files after creating.
(after writing a backup file, read it to see if ok - if not you will have a problem should it be eventually required)
Regards - Mike