Richard Cresswell had given Warnock's former club the lead a minute before half-time but impressive Moroccan midfielder Taarabt made it another frustrating day in the Championship for Blades fans, who once again vented their frustration at the final whistle.
Warnock, installed as Rangers' fifth manager of the season on March 2, steered the Londoners to home wins in his first two matches and while the point is further evidence of their progress since his arrival, it does little for the Blades' fading play-off hopes.
United manager Kevin Blackwell, who spent 13 years as goalkeeper, coach and then assistant to Warnock at a string of clubs before heading out on his own seven years ago, has endured rotten luck with injuries to key players throughout the season.
But his side have now taken just four points from their last five league games and the pressure is beginning to mount on the former Leeds and Luton manager. Warnock, making his fourth return to Bramall Lane since departing after relegation from the Premier League nearly three years ago, made no changes to his winning line-up.
Mark Yeates, Marcel Seip, Stephen Quinn and Henri Camara all returned for United.
Blades goalkeeper Mark Bunn did well to smother at the feet of Taarabt in the ninth minute when the visitors carved out the game's opening chance.
Camara then fired a return pass first time just over the crossbar at the other end after combining well with Yeates down the left.
Rangers were denied by the woodwork in the 19th minute as Hogan Ephraim's angled left-footed shot from 12 yards beat Bunn and came back off the upright.
But otherwise the first half was a disjointed affair, outstanding only for the number of misplaced passes by both sides, particularly the Blades, who were clearly low on confidence.
Bunn came to their rescue again in the 42nd minute when diving low to deny another skidding shot from Ephraim, who had raced clear on to Jay Simpson's incisive pass.
But then a rare thing happened. United winger Yeates got by his marker down the left a minute before the break, swung over a super cross and Cresswell steered a fine header into the top corner with visiting goalkeeper Carl Ikeme only able to help the ball into the net.
Rangers midfielder Taarabt then cashed in on some shoddy defending by Seip to haul the visitors level.
The Blades central defender lost the ball under his feet and Taarabt pinched the ball off him and ran 20 yards unopposed before sliding the ball under Bunn from just inside the penalty area.
Bunn then tipped over the Moroccan's free-kick soon after as QPR took the game to their hosts.
Darius Henderson, back from suspension, replaced United midfielder James Harper in the 68th minute and spurned a glorious chance to snatch victory for the home side two minutes from full-time.
Cresswell raced clear down the left and curled a fine ball across the face of goal, but Henderson, back from a three-game ban, appeared to freeze as the ball bounced in front of him at the far post.