Tijdens de opnames van Terminator Salvation claimde regisseur McG dat zijn film de goedkeuring had gekregen van James Cameron, de regisseur van de eerste twee Terminator-films. Dat was wellicht niet helemaal het geval. In een interview met UGO Movie Blog zegt Cameron dat hij het vierde deel in de reeks niet authentiek en vernieuwend genoeg vindt. Hij vindt McG's verderzetting van de franchise niet beschamend, maar voelt zich er toch wat ongemakkelijk bij. Letterlijk zegt Cameron het volgende:

Yeah I did see it. It probably didn't get a fair day in court because I had to watch it at night when I got home from work, over a period of two or three nights. I think Sam [Worthington] is remarkable in the film because, well, I think Sam is remarkable in anything he does. Interestingly, I think McG did a good job in the sense...I think he was almost too referential to the mythos of the first and second film. He over-quoted them in a way? It didn't feel to me to be enough of a reinvention. I mean the thing we did with the second film is that we reinvented the first film completely; spun it on its ass and made the Terminator the good guy, and came up with a whole new concept for a villain, it felt fresh. I didn't feel the fourth picture was fresh enough. It also lacked a certain stamp of authenticity because Arnold wasn't in it. I mean, he was in it briefly, digitally, but that's not the same thing. (...) I didn't think it was bad. I didn't think it was embarrassing. I don't think he let the franchise down in some huge way, but I did feel some sort of unease that it didn't go beyond.