We have identified an issue that causes players to crash during gameplay on Xbox and PC. We are actively working toward addressing this as quickly as possible, and will provide an ETA as soon as we have one available to share.
Update: This issue was due to a call to gamerpics while in free roam and race completion. We have resolved this issue. We are aware that there are other crash incidents and if you are still experiencing crashing, please check out our articles on the support page and submit a ticket.
https://support.forzamotorsport.net
Thank you