A method for use in conjunction with a horizontal directional drilling system during an inground operation including a pull-back operation in which a drill string is retracted by a drill rig to pull a utility at least generally along a pilot bore such that key-holing can take place wherein the utility is inadvertently displaced above an initial path of the pilot bore, said method comprising: forming the pilot bore by advancing a boring tool through the ground responsive to extension of the drill string from the drill rig while measuring a length of the drill string extending from the drill rig to the boring tool; as the boring tool is advanced, recording at least one parameter (922; 924; 926; 928; 930; 932; 934; 936; 938; 940; 942; 944) that characterizes the pilot bore at a series of positions along the pilot bore indexed against the measured length of the pilot bore for each one of the series of positions; after forming the pilot bore to a point where a distal end of the drill string can be accessed, attaching a pull-back tool to said distal end of the drill string and attaching the utility to the pull-back tool; retracting the drill string, during a pull-back operation, to pull the pull-back tool and the utility toward the drill rig at least generally along the pilot bore while measuring the length of the drill string extending from the drill rig to the pull-back tool; characterizing at least a current value of said parameter (922; 924; 926; 928; 930; 932; 934; 936; 938; 940; 942; 944) during the retraction indexed against the measured length of the drill string; comparing the current value of the parameter (922; 924; 926; 928; 930; 932; 934; 936; 938; 940; 942; 944), at a current location of the pull-back tool and obtained during the pull-back operation to a recorded value of the parameter (922; 924; 926; 928; 930; 932; 934; 936; 938; 940; 942; 944) taken during formation of the pilot bore and corresponding to the current location; and based on a deviation of the current value from the recorded value of the parameter (922; 924; 926; 928; 930; 932; 934; 936; 938; 940; 942; 944), initiating a response to drill string key-holing at least potentially occurring. forming the pilot bore by advancing a boring tool through the ground responsive to extension of the drill string from the drill rig while measuring a length of the drill string extending from the drill rig to the boring tool; as the boring tool is advanced, recording at least one parameter (922; 924; 926; 928; 930; 932; 934; 936; 938; 940; 942; 944) that characterizes the pilot bore at a series of positions along the pilot bore indexed against the measured length of the pilot bore for each one of the series of positions; after forming the pilot bore to a point where a distal end of the drill string can be accessed, attaching a pull-back tool to said distal end of the drill string and attaching the utility to the pull-back tool; retracting the drill string, during a pull-back operation, to pull the pull-back tool and the utility toward the drill rig at least generally along the pilot bore while measuring the length of the drill string extending from the drill rig to the pull-back tool; characterizing at least a current value of said parameter (922; 924; 926; 928; 930; 932; 934; 936; 938; 940; 942; 944) during the retraction indexed against the measured length of the drill string; comparing the current value of the parameter (922; 924; 926; 928; 930; 932; 934; 936; 938; 940; 942; 944), at a current location of the pull-back tool and obtained during the pull-back operation to a recorded value of the parameter (922; 924; 926; 928; 930; 932; 934; 936; 938; 940; 942; 944) taken during formation of the pilot bore and corresponding to the current location; and based on a deviation of the current value from the recorded value of the parameter (922; 924; 926; 928; 930; 932; 934; 936; 938; 940; 942; 944), initiating a response to drill string key-holing at least potentially occurring.