Hello GunnerBucci.
Please do the following:

• Hover over the DayZ card in the Xbox OS, press the start button and go down to "Manage Game and add ons"
• Go down to "Save Data"
• Delete the save Data for the account with the problem
• Select "DELETE EVERYWHERE", the other option will not solve the problem
• Note that doing this will close the DayZ client if its running

This should resolve the problem.

Regards,
Geez