She was due to pick up a Virtuosos Award for her performance in Bridesmaids at the festival, but missed out after coming down with laryngitis, according to WENN.
The Virtuosos Award, recognising the year's stand-out performers, was also handed out to Rooney Mara for The Girl with the Dragon Tattoo, Young Adult's Patton Oswalt, A Better Life actor Demian Bichir, Rise of the Planet of the Apes' Andy Serkis and The Descendants actress Shailene Woodley.
Festival director Roger Durling said: "I'm ecstatic about this strong line-up of Virtuosos. They all gave us indelible performances."
Last year's winners of the Virtuosos Award were Lesley Manville, John Hawkes, Jacki Weaver and Hailee Steinfeld.
McCarthy has also been nominated for an Academy Award in the 'Best Supporting Actress' category for her role in Bridesmaids.
Watch Melissa McCarthy discuss Angelina Jolie, Brad Pitt and Meryl Streep on The Ellen DeGeneres Show below: