I purchased FM5 about two months ago, inserted the disc, completed the updated download and played fine for a couple weeks. One day I received the “update” message when I started playing FM5 and completed this download. After the download the game crashes back to the home screen every time the Prague track tries to load. All of the other tracks load fine and play without issue. I’ve searched the internet in hopes of finding a solution without much luck. I see that people have deleted the game from their cache and downloaded it again, but I’m afraid that I will have to start my driver level all over and I will lose all of my cars. Does anybody know of a solution to this issue?
There is a Bug Report Thread on the FM5 Discussion forums. You can say about your problem there instead.
Peace
Try Re-installing the game without internet plugged in and don’t play until its fully loaded…
you wont lose your save or content as that is saved to the cloud 
So uninstalling the game won’t delete my save content in the cloud? How do I uninstall the game?
Goto my games and apps find forza then press what used to be the start button the one with the 3 lines while forza is highlighted then u will get a drop down menu uninstall will be at the bottom.
Also, if you are connected to a 10/100 Ethernet port with a wire, try changing to a wireless connection and reinstalling the game (and title updates)!
After problems with 20+ install attempts on two different Xboxes, this simple change finally got a few of us a clean install of all content. Very weird. We’ll hopefully have validation that the wired connection was the cause soon. Another option could be to put a decent gigabit switch between the Xbox and the router.
I am already using a wireless connection. When I purchased the game (disc) and put it in, I was prompted that I needed to completed a download. I did so and played after with no issues. After the recent update (a few weeks back) I get booted back to the xbox dashboard every time the Prague track tries to download. I already tried the “push and hold the xbox button for 10 seconds to reboot” and that did not work. I don’t have a problem with uninstalling the game and reinstalling if I don’t lose my driver level, cars I’ve purchased, designs that I have created and credits that I have earned. Does uninstalling the game also erase these things? If not, how do I do an uninstall and then reinstall?
I didn’t lose any progress or saved game data in my reinstalls.
There’s probably something in the Help documentation, but I think an uninstall can be performed by highlighting the game’s icon in the app list, pressing the “menu” button on the controller, and selecting uninstall.