Forza Horizon 3 owners on Windows 10 experiencing issues with latest update [Update: fixed, new version available]

Update 06/01/2017
As of 10:15 this morning, Turn 10 has pushed a new updated version of Forza Horizon 3 to Windows 10 PC users, bringing the version to 1.0.39.2.  First seen on Twitter, the team notified users that the update will unify those who both did and did not download the broken update on Tuesday, as well as add the promised Rockstar Energy Car Pack that was supposed to release on Tuesday.  The original tweet is included just below, so go check those downloads and get driving in the latest car pack.

Update 05/01/2017:
Ekburg has updated his original post with further information regarding the broken update for Windows 10’s Forza Horizon 3 update on Tuesday.  Ekburg writes that the developers at Turn 10 are working to prepare the correct update for PC users and, though it will not release today, he is hopeful that it will be available “as early as tomorrow”.  He preceded this by saying he doesn’t know or have a precise ETA for the update’s release, but that he will again update his post on the forums, linked as our source at the bottom, when he does and the update is rolling correctly.
Original article:
Earlier today, Turn 10 Studios announced and released the latest car pack, the Rockstar Car Pack. During the first hour of the stream on the Forza team’s Beam and Twitch channels, fans on Windows 10 were reporting issues with the download. While the typical update size for Forza Horizon 3 for a car pack is between 3 and 5 GB, this update asked Windows 10 users to download the entire 50+ GB game. Turn 10 Studios is aware of the problem, and actively working on remedying it.
According to Turn 10’s Community Manager Brian Ekberg, “The incorrect PC version of FH3 has now been removed and replaced. PC Players who have the FH3 version ending with .37.2 should immediately uninstall that version of the game, then re-install. The correct playable version should end in .35.2.” This update comes at just after 1:30 p.m. PST, and there is an interesting aspect to note if you have already downloaded the .37.2 update.
Ekberg notes that if you already had a saved game profile and continued that profile in .37.2, there is currently no known problem. The problem, he explains, occurs when a player creates a new game save in the .37.2 update, because that file will be corrupted.
As of now, Forza Horizon 3’s .37.2 update has been pulled from the store, with .35.2 being the most up-to-date version. There have not been any remarks made regarding the release of a fixed update. We’ll update the post when new information is revealed, so check back throughout the day to stay up-to-date.
Source: Brian Ekberg via Forza Forums