Using the option “-r -1” lets the program first go through the whole disk and afterwards try to recover the bad blocks ENDLESSLY. The message “Splitting error areas…” indicates this. From that moment on you can interrupt by pressing Ctrl-C as soon as you cannot stand the waiting any more.
sudo /Applications/ddrescue110/ddrescue -v -r -1 /dev/disk4 /Volumes/Bay_2_R3/Rescuefolder/rescuefile.dmg /Volumes/Bay_2_R3/Rescuefolder/rescue.log
Super Site containing information about ddrescue:
The sourcecode with install description is available:
Information about issues with “Resource busy” issues are here:
“Open the DiskUtility.app, and on your USB hard drive, unmount any of it’s partitions. Do not eject the USB hard drive.”
Comprehensive Manual at: https://www.gnu.org/software/ddrescue/manual/ddrescue_manual.html