The 26-year old New Zealand international joined Celtic as a 15-year old back in 2002 and could have signed a pro deal with United just a couple of years later.
However, McGlinchey admits that decision is one he certainly does not regret as he prepares to take on the Red Devils with the A-League All-Stars this Saturday.
"I've thought about it, don't get me wrong," said McGlinchey.
"But I try and live with no regrets. At the time I made the decision to stay at Celtic and I thought that would've been the best thing for my career.
"Obviously I learned a lot from being there and it's helped me in my career so far."
McGlinchey did train with United for a week and admitted it was a great learning curve for his career.
"I was very fortunate to go down there and see the way these sort of guys play, I definitely took a lot from that week," he added.
"I was only 15 at the time, so I was training with the 17s, 19s reserve team ... but a lot of them went and made careers out of it." The game is about opinions. Make yours heard! Join thetribalfootball.com nation on Facebook today: Facebook.com/tribalfootball