Project Car's on my Xbox one stopped saving Data.

Check this link for a possible solution:
https://support.xbox.com/en-US/games/troubleshooting/cloud-storage-sync-error-messages

It gets better. Multiple xbox gamers are reporting that Project Cars 2 will randomly delete your career save-game data, without warning. Here's their official forums

http://forum.projectcarsgame.com/showthread.php?51983-Career-progress-gone

I just uninstall the game, to save my data, when i install the game, i choose the saved data from the xbox, because it said that is the newest saved data and i start with a horrible car and with 50k

Also, I was thinking of moving all my Banjo series save data to the cloud so I could access it on the Xbox One, but I don't think I have enough space to move all my vehicles. Could I just move my save data and still access my cars?

Hi,

Accessing and syncing game data and in-game contents online may experience issues that vary on its cause. Make sure to sign in with the Microsoft account that was used to purchase the game.

To help resolve your concern with Forza Horizon 3 on Xbox One, refer to the following solutions:

Solution 1: Clear Persistent Storage

1. Scroll left on the Home screen to open the Guide.
2. Select Settings.
3. Select All Settings.
4. Select Disc & Blu-Ray.
5. In the Blu-Ray section, select Persistent Storage.
6. Select Clear persistent storage.
7. Restart your Xbox One console. Access the game again and check if the same instance occurs.

Solution 2: Clear MAC Address

1. Scroll left on the Home screen to open the Guide.
2. Select Settings.
3. Select All Settings.
4. Select Network.
5. Select Network settings.
6. Select Advanced settings.
7. Select Alternate MAC address.
8. Select Clear.
9. Select Restart. Access the game again and check if the same instance occurs.

Solution 3: Remove and re-add your Microsoft account on Xbox One

Refer to this
link and perform the steps provided. Make sure to restart your Xbox One console before re-adding your Microsoft account. Then, access the game again and check if the same instance occurs.

Solution 4: Reset your Xbox One to factory defaults

1. Scroll left on the Home screen to open the Guide.
2. Select Settings.
3. Select All Settings.
4. Select System.
5. Select Console info & updates.
6. Select Reset console.
7. On the Reset your console? screen, select Reset and keep my games & apps. You should use this option as your primary choice when troubleshooting. It will reset the OS and delete all potentially corrupted data without deleting
   your games or apps. This will save you from downloading or reinstalling the large game files. After its completion, access the game again and check if the same instance occurs.

If anything comes up, let us know so we can provide further assistance.