Play the game for 5 minutes, complete one quick race, and close the game. Reconnect to the internet.
Navigate to your respective save path (listed in Section 2). forza horizon 5 1.405 save game
Save files are cryptographically tied to specific Steam IDs or Xbox XUIDs. Dropping someone else's save into your directory will usually result in an "Invalid Profile" error on launch. Play the game for 5 minutes, complete one