User view suddenly not working - error when trying to edit

Hi I came to my user view to assign project rights to a user and when i tried to edit I got this error (and cannot find any content on fixing it) - Please help! Thanks in advance View error Can't find field 'in_group_63' in the following view parts composing the view of object model 'res.users': * res.users.groups Either you wrongly customized this view, or some modules bringing those views are not compatible with your current data model