The 28-year-old from Grantown-on-Spey opened her round with a birdie on the par-5 first hole and followed that with two more on holes six and seven.
“I would always take four-under for the first round. It was really windy, and I played the course yesterday for the first time so I’m pretty delighted actually,” commented McCook.
The Scot dropped a shot on the par-4 eighth to make the turn in 35 as the wind started picking up in the north-east of England.
“What works for me the most playing in such windy conditions is trusting the shot that I’ve got and trusting that I’m aiming far enough sideways when it’s a crosswind,” she added.
McCook, who took a two-year break due to the pandemic followed by an injury, is chasing her first professional win.
She came close in the last month as she finished runner-up in Montauban and then tied for fourth in Saint-Omer last week.
“I have my mum on the bag this week which is really nice,” said McCook, who sits 11th on the LETAS Order of Merit.
“The last time she caddied for me was in 2019 and she caddied a lot while I was still an amateur in 2018 when we won a couple of times together.”
In the amateur ranks, meanwhile, Scotland comfortably qualified for the top flight in the European Ladies’ Team Championship in fourth position at Conwy in north Wales.