InvalidOperationException: fieldTypeItem
If you are getting the following error after sitecore upgrade while clicking on inheritance tab for a particular item. and logs showing following error. Exception: System.InvalidOperationException Message: fieldTypeItem Source: Sitecore.Client than make sure that config updates are done properly. Then after, if you still getting this error. Check the fields defined on the template of item. If there is any field's type box seems empty then fill it's value. If no field's type is empty on this template then check the inherited templates by clicking on "Raw Value" in "View" Ribbon's tab. Copy this template id and look into it's fields defined, for field's type check. Do this for all templates it's inheriting. If you see any field empty as in following image (for "Headline" field). Change the type to "Single-line-text" or whatever your field's type is. And don't forget to publish after save if you