Moyes vacated his job at Everton to take over the United reins from his retired compatriot in the off-season of 2013 after being recommended by Ferguson.
However, the Scot oversaw a disastrous first season at Old Trafford, which culminated in his sacking in April after the Red Devils failed to qualify for the UEFA Champions League for the first time since 1995.
The appointment had always raised questions given his Toffees credentials, but Ferguson opined in a new chapter of his 2013 book, My Autobiography, that Moyes simply misjudged the scope of the club.
Ferguson said: “There appears to be an accepted view out there that there was no process. Nonsense. We feel we did everything the right way: quietly, thoroughly, professionally.
Commenting on Moyes, he added: “He hadn’t realised just how big United is as a club.”
The 72-year-old believes a part of the problem at United last season was that his three lieutenants, Mike Phelan, Rene Meulensteen and Eric Steele were not retained by Moyes, who bought in his own backroom staff.
Ferguson wrote: “Maybe David felt that at such a massive club he had to be sure that all corners were covered in terms of his support system. I felt that network was already there, with plenty of great people already in important slots.”