Although attributes are saved with the project, it can still happen that your project contains elements which refer to missing attributes. You will notice this in the element’s Settings dialog box, as in the case of the missing line type referenced by this door:
Missing attributes may occur:
•if you have copy-pasted elements from a different project using a different set of attributes
•if you have placed objects whose GDL script refers to attributes missing from your project
•if you have removed used attributes from your project via Attribute Manager
•if you have removed used attributes via Delete and Replace Layer
To locate elements referring to missing attributes, use Find and Select.