This tool checks all parts of a group of elements with the same part mark to see if they are still identical. If the parts are no longer identical, they need another part mark. This is the case if they were changed after the numbering.
To access the command
Ribbon: Output > Part marks: 
Command line: _AstM5CommEqualPartsWithoutNum
To check duplicate part numbers
- Output tab, Part marks panel, switch to the single part or assembly.
-
Output
tab,
Part marks
panel: Click .
- The list of found errors (incorrect part marks) is displayed in the AutoCAD® text window.