@jcfm: A few comments below...
jcfm wrote:I wave an external disk usb 40g with bad sector
When a disk starts to have bad (unreadable) sectors, it may not be worth trying to fix it (and attempts to fix may not be successful, if there is an underlying fault).
jcfm wrote:y have run hdd regenerator it repair some bad sector but not wall.
Perhaps this was not successful, because the drive is more faulty than you thought?
jcfm wrote:I now running hd llf tool 2.36 build 1181 and various “format error occurred at offset ….” messages appears.
Although I have not seen "official" support for that program here, again that message suggests that the disk is reporting errors to the commands sent by llf tool.
You can try using any "zero fill" or overwriting tool (Seagate Seatools, WD DLG, MHDD etc etc), if you want to try to make the disk reallocate any currently-recognised unreadable sectors. Better would be to perform a full read scan followed by a zero fill, to try to find all unreadable sectors. However, if you see errors from these programs too, then that probably means the drive really is faulty.
Is all this effort really worth doing for a 40GB disk drive, which could just be reaching the end of its life and hence becoming unreliable? Do you
really want to store data on this disk, if it is unreliable? It's your data so it's your choice