North End have endured a dreadful campaign and have now won only four of their 19 matches this season.
Ferguson's men huffed and puffed at Deepdale but they could not break down a spirited Millwall outfit who stood firm to earn a deserved share of the spoils.
With skipper Callum Davidson missing through injury, Preston handed a debut to Burnley defender Leon Cort after he joined the club on loan earlier this week.
North End were desperate to bolster their back line after a woeful start to the season which has seen them shipping goals at an alarming rate of knots.
They had already lost six times on home soil this season and Ferguson knew another loss at Deepdale would spell disaster.
The early signs were encouraging as striker Jon Parkin collected possession inside the opening minute and fired a shot wide from six yards out.
Yet Millwall steadied themselves and gradually gained a foothold.
In the ninth minute Lions forward Steve Morison collected possession 20 yards from goal and unleashed a fine shot which drew an equally impressive save from home goalkeeper Andy Lonergan.
Two minutes later Preston went close when midfielder Darel Russell hit a left-foot shot wide from 20 yards but Millwall's James Henry also had a near-miss soon after with a similar long-range effort.
Morison shot wide again for the visitors as genuine goalscoring opportunities remained scarce.
The Lions made a substitution in the 20th minute when Liam Trotter was replaced by Nadjim Abdou in midfield.
Preston threatened again in the 28th minute when Russell drove a shot wide from 12 yards.
He threatened again with a 25-yard strike in the 33rd minute but neither side could make the breakthrough before the interval.
Highly-rated Preston midfielder Adam Barton then hit a 25-yard shot wide and in the 63rd minute an outswinging centre from Henry fell to Paul Robinson, who fired goalwards from six yards but failed to hit the target.
In the 68th minute, Millwall's Calvin Andrews drilled an 18-yard shot wide and moments later, an inswinging corner from Keith Treacy was greeted by a firm header from Billy Jones but his effort flew over the crossbar.
Morison went desperately close in the 72nd minute with a 12-yard strike which Andy Lonergan did well to tip around a post and he then headed over in the 81st minute as neither side could break the deadlock.