ATI task stops at failure of hdd not involved in the task

ATI Home 2009
Two hdd disks are installed in system. Both are magnetic hdd, no ssd.
Hdd (A) has several partitions, including the system partition.
Hdd (B) has two partitions, and one unallocated area between them two.
ATI sees and reports these disks as disk 1 - the (A), and disk 2 - the (B).

ATI tasks makes an backup of few files located on disk (A).
The backup file is also placed on (A).
So (B) is no way involved in the ati task.

If to start the task it stops few seconds after its start with
the error message "Failed to read from the sector 73.686.777 of the hard disk 1".

Why is ATI doing so?

Neither the OS nor any application reports problems with partitions located
on (B). Chkdsk executed for all partitions existing on (B) didn't report any failures.