In television the 9th Season of Dallas aired from 1985-1986 but was retconned away as a dream Pamela Barnes Ewing had, in the opening of the 10th season, thus becoming known to fans as "The Dream Year" or "the Dream Season". I believe that this was done because many fans were upset by plot developments in that season.
In movies the James Bond series was rebooted with Casino Royale in 2006. Thus Casino Royale (2006) and its sequels are not sequels to the previous James Bond films from Dr. No (1962) to Die Another Day (2002). And Casino Royale (2006) and its sequels do not happen in the future of the previous James Bond films from Dr. No (1962) to Die Another Day (2002).
And within the sequence of James Bond movies from Dr. No (1962) to Die Another Day (2002) there are two special cases. Casino Royale (1967) was produced by different persons and had a different plot and continuity from the James Bond movies produced by Eon Productions. Never Say Never Again (1983) was also not produced by Eon Productions and has the same basic plot as Thunderball (1965). Thus Never Say Never Again (1983) and Thunderball (1965) might be considered alternate universe versions of the same story.
But I don't think that any of those alternate universe versions or reboots is due to fan dissatisfaction with the course of the James Bond Series.
In the Star Trek the four movies made in the 1980s were a series of sequels. Star Trek II: The Wrath of Khan (1982) was a sequel to the TOS episode "Space Seed". Star Trek III: The Search for Spock (1984) was a sequel beginning soon after the ending of the previous movie, and ending with the protagonists on Vulcan. Star Trek IV: The Voyage Home (1986) opened in the "3rd month" of their Vulcan exile, as they prepare to return to Earth and face the music for their actions in the previous movie; and ends with Kirk getting a new ship the USSS Enterprise 1701-A. Star Trek V: The Final Frontier (1989) is less connected to the previous films but begins with the new ship having a lot of problems.
In Star Trek fandom Star Trek: The Motion Picture (1979) and Star Trek II: The Wrath of Khan (1982) are often divisive, with fans arguing about which was better. And many believe that the creators of Star Trek II: The Wrath of Khan (1982) deliberately ignored Star Trek: The Motion Picture (1979) and more or less tried to retcon it out of existence. Similarly the creators of Star Trek VI: The Undiscovered Country (1991) may have ignored Star Trek V: The Final Frontier (1989) and wished it had never been made. Star Trek VI: The Undiscovered Country (1991) mentions events in Star Trek II, Star Trek III, & Star Trek IV, but doesn't mention any events from Star Trek V.
Gene Roddenberry, creator of Star Trek, considered that some of the plot elements in a particular movie or TV episode could be canonical while others were not canonical. Roddenberry considered Star Trek: The Animated Series (1973-1974) to be canonical until he decided it wasn't canonical, and considered some aspects of Star Trek V: The Final Frontier (1989) and Star Trek VI: The Undiscovered Country (1991) to be non canonical.
Thus many fans and creators of Star Trek consider some movies, episodes, and TV series to be non canonical. Of course Paramount is happy to continue making money from even the most despised and controversial Star Trek movies, series, and episodes and would never think of decreeing any Star Trek production to be non canonical or not worth watching.