When Harry and Marin are driving to Erica's house in the Hamptons, Marin tells Harry to make a right. But in the next shot, we clearly see them turning left.
As Harry and Marin drive to Erica's house, the road has no lines. When they turn onto to the dirt road which leads to Erica's house, there are now white double lines down the middle of the road.
The last scene in Paris is supposed to be in January. When Harry is on the bridge you can see trees with leaves on the river bank.
When Harry and Marin arrive at the Beach house for the very first time, she can clearly be seen, from behind, wearing a small white thong under her white jeans. In the very next bedroom scene she has removed the jeans, and has suddenly changed into big knickers.
When Erica is on her Apple, sometimes the computer has cords connected in the back which is not possible on a Mac laptop of that vintage; later when she closes it, there are no cords or even connecting slots as is correct for a Mac laptop.
Someone trained in CPR would know that you don't start compressions or mouth to mouth on an awake person who clearly is breathing and has a pulse.
When Erica returns from the restaurant after confronting Harry, she picks up her phone messages and the system says she has 1 new message. It was from Julian. But just prior to that, Harry had called Erica from his apartment and, although he didn't speak, he had activated Erica's voice mail past the beep, so there should have been two new messages - one of them dead air.
When Marin calls for an ambulance, she gives an address in Sagaponack, which is in Manhattan, not in the Hamptons.
After Erica and Harry's long walk on the beach, the sun is obviously low in the sky, and Harry asks if Erica would like to watch the sunset with him. She can't, because she has to get ready for her date with Julian. The date was set up for 7:00, so it must be no later than 6:30. It's the middle of the summer, so the sun shouldn't be setting for at least another two hours.
When Harry and Erica are walking on the beach, you can see the tire tracks made by the camera dolly in the sand behind them.
When Julian and Erica are having dinner in the restaurant, Erica appears to be reading her lines from a teleprompter to the right of Julian's eyes. Done very well... but... she doesn't appear to be looking into his eyes... but... just to the right of his eyes (viewer's left).
When Harry speed dials Erica in his apartment, we hear the rapid dial tones. Cell phones don't make these sounds.
When Erica and Harry walk at the beach the shadow of the tent-van is visible, actually moving with them
When Harry and Marin are talking outside before going in the house you can see the camera lights in Harry's sun glasses.
When Harry is getting wheeled out of the hospital, the camera turns on the other characters waiting for him in the parking lot. Although they were supposedly in the Hamptons, there is a palm tree and a California hill in the background.
Even though Erica is lighting candles because the power has gone out, Harry is still able to turn on the stereo, surprising Erica.
Erica writes the script of her play in the wrong format.
Marin says the following within a two-minute span: "I am almost 30 years old," "Dad is marrying someone who is only two years older than I am," "Dad is marrying a 33-year-old." These statements cannot all be true.
When Erica emails Harry, she spells the plural of PJs, 'PJ's', with an incorrect apostrophe.
At minute 56, when the daughter is leaving, she says 'Erica' instead of 'Mom'.