The early warning went unheeded and managerless Fulham found themselves trailing five minutes later when Joe Garner popped up at the back post unmarked and headed home.
Preston defended tightly, but Fulham came close to an equaliser in the 69th minute when Tom Cairney shot on the turn, forcing Pickford to tip his effort over the bar.
The home side were much improved in the second period and they netted a deserved leveller in the 77th minute when McCormack hit an inch-perfect free kick into the top corner.
There was bad news for Preston in stoppage time as Stevie May was stretchered off with what looked like a serious injury following a challenge by Richard Stearman, leaving the field to a round of applause.
The result leaves Preston in 18th position in the table, four points behind Fulham in 13th.