“Microsoft.SharePoint.SPException: One or more field types are not installed properly.” Using SPQuery

Have you run into this error? “Microsoft.SharePoint.SPException: One or more field types are not installed properly.” ? Well I did, I was banging my head into the wall, until I realized that the fields had been renamed at some point, and when referencing splistItem[”FieldName”] in my code, it was not recognizing the updated name. So make sure you reference either the GUID or the name it was before renaming.