Revealing mistake: When Phil is looking for Will who is in Ashley's room he slams one door shut and the set wall can be seen to wobble. (00:11:00)
Continuity mistake: When Hilary starts crying, Tyrone is wearing an apron. In the following shot he is suddenly not wearing it, but in the next shot it is back on. (00:12:55)
Burnin' Down the House - S6-E1
Continuity mistake: The cognac bottle is almost empty when Will passes by the counter, but when he turns around to pour the liquid, the bottle is full.
Audio problem: When Jerry goes over to open the jail cell door, the sound effect of jingling keys can be heard, however the actor isn't holding any keys. The jail cell door doesn't even have a keyhole.
Suggested correction: When the Sergeant tells Jerry to open the cell (00:18:20), Jerry reaches to his left side to retrieve keys from his duty belt (there is no "sound effect of jingling keys"). And keys were visible dangling from Jerry's duty belt when he told Philip to calm his wife (00:17:10). Secondly, the jail cell door does indeed have an old-style keyhole (00:18:30).
Other mistake: When Will confronts his mother about not wanting to move back to Philadelphia, she mentions she can't afford to send him to an out of state school. However, in season 2 it's already been established that Uncle Phil is Will's legal guardian, and he's a resident of California. Will's mother has it backwards. Going to school in Pennsylvania would be an out of state school and staying in California would be in state.
Continuity mistake: A member of the poetry club responds to Will's "You're a poet and you don't know it!" with a sassy "I -AM - a poet and I -DO - know it" in a close-up. In said close-up, she is holding her hand on a book, while in the shots before and after, her arm is in a different position. (00:06:30)
Not With My Pig, You Don't - S1-E4
Continuity mistake: During the award dinner, when Hattie says the line about "Zeke sprung from the ground like a big ol eggplant," watch the table in the back, next to the door. The man sitting there wipes his mouth raising a napkin 3 times in 3 separate shots. (00:19:00)
Character mistake: When Geoffrey serves tea after his sassy cough at Vivian's sentence about High Tea not being a sacred institution, the actor messes up when it's time to actually serve tea, with a napkin getting caught in the teacup saucer. Granted, accidents do happen, but it's quite uncharacteristic for the perfect butler Geoffrey is portrayed to be, and simply a flub by Joseph Marcell. (00:17:45)
The Fresh Prince Project - S1-E1
Revealing mistake: When Will screams in front of the mirror, imagining himself turned into Carlton, something went wrong making the composite shot and not only you can actually see the line of separation between the two frames, but the superimposed one exposes a bit of the mirror woodframe before it wiggles into the correct position and covers it up. (00:11:30)
The Fresh Prince Project - S1-E1
Continuity mistake: When Will puts the last of his wall-shaking staples on the Malcolm X poster before the butler's interruption, the poster is almost perfectly flat. When Geoffrey walks to the poster, a bottom corner is noticeably raised. When Carlton walks to it, it's flat again, and raised when Will freaks out at the mirror. (00:07:40 - 00:10:00)
Clubba Hubba - S1-E3
Revealing mistake: During his first conversation with Dr. No, Will Smith mouths "strings of Arabians" as Richard Roundtree says it (it can't be a line he rehearsed with Carlton, because his character has no clue about that branch of conversation). (00:11:00)
Clubba Hubba - S1-E3
Continuity mistake: As Carlton and Will battle out with their "I bet he won't", "I bet he will", Will is holding his drink with his left hand. When he breaks the fourth wall with a joke in a new shot, the glass switches hands. (00:05:00)
Continuity mistake: When Ashley shows Will her weekly schedule, her hand is towards the middle of the upper roll of the parchment, but in the reverse shot where the calendar can be read, her hand is at the top right corner. (00:03:30)
Continuity mistake: When the family kisses Will goodbye and when he sits bummed out on the couch, the pool float around his arm switches position, going under his left arm, then under his right, then left again. (00:02:50)
Homeboy, Sweet Homeboy - S1-E5
Continuity mistake: When Ice Tray announces that Hilary and him got married, Mrs. Banks' glass is suddenly emptier, going back to almost full just a moment later. (00:17:45)
The Fresh Prince Project - S1-E1
Visible crew/equipment: During Will's first introduction to Uncle Phil the camera tilts slightly down to Will and Aunt Vivian on the couch and the boom mic drops into the frame briefly.