Character mistake: Morgan Hiller's father is named Stewart (according to the story as well as credits). But in one scene when Morgan and his parents are having dinner, Mrs. Hiller calls him (her husband) "David" one time (instead of Stewart).
Visible crew/equipment: During the final battle, when the Ewoks swing on the ropes, a crew member's hand is visible pushing one of them forward.
Continuity mistake: When John Candy is woken up by his wife after getting drunk with Scully, he has a hoop earring in his right ear. Later during the regatta, the earring appears in his left.
Continuity mistake: Everyone wears the same outfit during their hunt for Big Bird. Maria's changes to a dress once they arrive in Toadstool.
Visible crew/equipment: Near the beginning, at the start of the big car chase down the hill, there is a guy blocking another guy's vehicle. The blocking car is red and backs up before turning onto another road. The reflection of the entire camera crew is visible in the side of the red car.
Audio problem: When the husband (Hector Elizondo) is seated in the barber chair, he's heard talking to the kid, but his lips aren't moving. An obvious audio sync issue.
Other mistake: When Dagg hits the soldier on the left while the fembot is distracting them, he falls over and the one on the left turns to see what happened. It then cuts to a different view and suddenly the second soldier just falls over without even getting hit.
Continuity mistake: During the scene when Andrea's talking about suing the club, the amount of papers in her hands change from 4 to 5 in between shots. (00:44:20 - 00:45:21)
Continuity mistake: When Dalton is having his picture taken with his camera by the blonde next to the pool, she has his camera. Christopher confronts him, then in the next shot Dalton now has the camera and the blonde is holding red roses.