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Error: AcRxClassName or Error: Exception Occurred (Placing a Reference Note Callout, MLeader, or Work Area)


When placing a Reference Note callout, any callout that uses multileaders (MLeaders), or a Work Area, you received an error message containing the text AcRx, or one or all of the following: 

  • AcRxClassname
  • Error: 'AutoCAD.Application: ACRxClassName entry is not in the system registry
  • Calling method SetObjectId of interface IAcadBaseObject failed
  • Error: AutoCAD application calling method set object ID of interface AutoCAD based object failed
  • Error: Exception occurred


This error may have popped up when you were trying to work with one of the following callout types:

  • Reference Notes Callouts
  • Any site callout with text
  • Detail leaders with text
  • Plant labels



You can address this error by repairing the registry file associated with MLeaders and Work Areas.


First, download the MLeader Fix Files zip file linked below.



Clicking the link above will create a file named in the location where your downloads normally go, such as your Downloads folder or your desktop.



Locate the file, and double-click it to unzip it.


This step will create a file named mleader-fix in that same location.




Open the folder mleader-fix. You will see several files with the .reg extension.



Double-click the file that matches your version of AutoCAD or F/X CAD.



For example, if you have AutoCAD 2019, double-click the file mleader 2019.reg.




You should now be able to place MLeaders or Work Areas without seeing the error.

Last modified on Sep 23, 2020


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