Model-Based Definition > Geometric Dimensioning and Tolerancing Advisor > Advisor Message Help > Datum Messages > Target Reference Is Missing
  
Target Reference Is Missing
The CAD object referenced by a datum target is missing. This problem causes the datum to be considered a failed object, as indicated by a separate 'There are failed objects in the model' message.
To fix this problem, you should edit the feature that the datum is associated with, and then redefine the datum from targets for that feature.