Hi Tiago, I'm sorry to hear you're having issues with this user's quota. This behavior indicates the user's settings.json file (found at the root of their directory on the server) has become corrupted or is otherwise missing. To correct this you can stop the SmarterMail system service, then restore a backup copy of this file from the user's Archived Data directory where we keep several days worth of backups of all user JSON configuration files. If you see this often I recommend getting a ticket submitted with us so we can help you track down the root cause. I hope this helps!