Corrected entry: Kate asks Alex to rescue her copy of Jane Austen's 'Persuasion' from the train station bench. Alex tells Kate he will save it for her for when they meet. Then, in her apartment bedroom at 1620 Racine that she's sharing with boyfriend Morgan, Kate checks a loose floorboard to find that book hidden beneath; though the story makes clear that Alex has never been inside the apartment.
Corrected entry: When Alex finds his dog at Morgan and Kate's house, his girlfriend comes running up and says "Thank God you found him." The dog is a female and she surely knew that.
Correction: This reflects on the girlfriend in that she has no idea if the dog is a boy or a girl because she doesn't really care! She's interested in Keanu as a boyfriend but not that interested in him as a person, hence why she doesn't bother remembering if it's a boy or a girl.
Corrected entry: In the scene where Kate is sitting at a bar, another woman (Dr.) comes in and sits on her left, but in the next shot she is on Kate's right.
Correction: They were showing a shot from the mirror behind the bar.
Corrected entry: When Jack the dog runs up the ramp being painted, he makes footprints but when Keanu immediately runs after him he makes no footprints, though it would still be wet.
Correction: The dog stepped in a paint tray and tracked that paint across the ramp. That is what left the prints. Unless Reeves stepped in it also (which he didn't) he would not have left prints.
Corrected entry: When Sandra Bullock's 2006 boyfriend tells her he's landed a job and is moving to town, he tells her he'll be working for a company as an "in house counsel," but shortly thereafter we see him in a storefront "Attorney at Law" office.
Correction: When we see him at the store front, it is in late 2004, this is when Alex moves out of the house, and gives him the keys, so Kate and Morgan can have the lake house. At some point after that he moves away, then comes back in 2006, this is when he has the in house counsel job.
Corrected entry: When Sandra Bullock is lying on her bed writing to Keanu Reeves halfway through the movie, she says she likes to read to Jack (her female dog). Keanu Reeves asks what "he" (the dog) likes to listen to, even though Keanu should know the dog is a "she" because he used to own her.
Correction: He didn't know that it was his dog yet. He didn't know her name either, so when she said her dog "Jack," he assumed that it was a male.
He did know it was the same dog. They already discussed having the same dog in a scene previous to this one when he even called the dog Jack and it responded. Also, she (the dog) was led upside down when he looked over at her and called her Jack so surely he noticed she was female.
Corrected entry: Kate is in the future and has named the dog Jack and informs Alex of this in a letter, which he receives in a magic time-travel mailbox. Alex adopts this same dog in the past, before the dog has ever met Kate. Jack tests out the name "Jack" on the dog, and the dog reacts to this name. The dog should not know this name as it hasn't yet met Kate. This is backwards. Alex should have been the one to tell Kate of a name he gave to the dog, and she should have been the one to test it on the dog.
Correction: Jack the dog is magical, like the mailbox. Neither character knows where he came from. The dog is a sort of guardian. He runs to the past from the future. Re-watch the film, and this is clear. This interpretation is important for enjoying the film, if even more illogical than a magical Lake house without a magical dog.
Corrected entry: The reason Sandra Bullock buys the lake house is because she witnesses Keanu Reeves' death. She "meets" Keanu Reeves because she bought the lake house. In order for this to happen, Keanu has to die in her time, yet at the end of the movie, he lives therefore she never would have bought the house or met him.
Correction: By the time Kate witnessed Alex's death at the Plaza not only had she and Morgan already bought the Lake House, they'd already moved OUT. (She left the note for the 'new' tenant first THEN saw Alex die.) Kate had already met Alex two years earlier at her birthday party (at her old house - at this point Alex is still living at the Lake House), and the only reason she and Morgan were able to move in to the Lake House was because Alex moved out and gave Morgan the keys because he knew it was what Kate wanted. Kate's buying the LH was nothing to do with Alex's fate.
Kate rents (not purchases) the LH. She rents it while finishing her residency "in a small hospital up along the North Shore." The birthday party is at Morgan's house (not Kate and Morgan), and is described by Kate telling Morgan about his jumping "10 steps" ahead and inviting the whole town to the party. Kate breaks up with Morgan about the time of the b-day or when she moves to LH. Alex has no address for Kate, but has Morgan's card and can give him the keys. No evidence Morgan ever visits LH.
Corrected entry: Jack the dog appears from nowhere early in the movie and is taken in by Alex. In the future, Kate, who has not yet met Alex, owns Jack and mentions her name in a letter sent to Alex. Since at that point in the film their paths had not crossed in either present or future, where did the dog's name come from? For that matter, where did the DOG come from?
Correction: I remember her saying " come on Jack, come on Jackie!" Jackie was said very quickly.
Corrected entry: When Alex gives his dad the coffee, his dad comments on how hot it is. Yet there is a close-up of the cup, and not the slightest trace of steam is coming out of it.
Correction: Steam is produced not from excessive heat, but from a large contrast in the coffee and the surrounding air temperature. If the temperature in the room were 80 degrees, which is feasible, and the coffee temperature were 95 degrees, then there would not be any steam coming off of the coffee, even though Alex's dad considers it "hot".
Correction: When I saw the scene in which Kate discovers the book under the floor, I immediately thought that Alex, at some point, went into the apartment building while it was still in the process of being built and furnished and hid the book there. He, as an architect and builder was able to pull it of and thus fulfill his promise of bringing her the book. He did it sometime after they broke up and before Kate moved in. I therefore believe this was not a plot hole but a clever idea that fits the movie perfectly.