In that book, Kogge wrote that C-3PO’s memories were flicked on, starting with what appeared to be his initial activation (an event that occurred in “Star Wars: Episode I — The Phantom Menace”). The passage reads as follows:
“This caused a memory file that R2-D2 had restored to be accessed and read. It was a record of the moment when C-3PO’s maker had fitted a photoreceptor into his eye socket and he had experienced the visual spectrum for the first time. The initial image his photoreceptors had captured was of a blue-and-white astromech.”
One might assume that C-3PO, with his earliest memory intact, remembers everything that he experienced throughout the many films and TV shows in the “Star Wars” franchise. Which might come as a shock, given that he witnessed wars, murder, and at least one incestuous kiss. This presumed complete memory restoration is, of course, one of those semi-canonical details that isn’t stated explicitly in any film or TV show, so Starwoids (as “Star Wars” fans are commonly known) are permitted to debate how accurate that might be.
Additionally, an even newer “Star Wars” tome explains that Kogge’s novelization isn’t telling the whole story. Marc Sumerak’s 2023 book “Star Wars: The Secrets of the Wookiees” is narrated by C-3PO as the droid recalls his friendship with Chewbacca the Wookiee. The audiobook is narrated by Anthony Daniels, giving “Secrets” a distinct canonical underpinning. And, by that book’s estimation, C-3PO’s memories are still a little spotty. He remembers some of the Skywalker Saga, going back to the beginning, but not all of it.