Compare VIs Greyed Out in LabVIEW

Updated Jun 14, 2018

Reported In


  • LabVIEW
  • LabVIEW Professional

Issue Details

I am trying to compare my LabVIEW VIs but the Compare VIs... option is greyed out. Why can't I use the Compare VIs tool?


Ensure you are selecting Tools >> Compare >> Compare VIs from the Front Panel or Block Diagram of one of the VIs you would like to compare. The Compare VIs tool must be selected/used from the Tools menu on a VI Front Panel or Block Diagram, not from a LabVIEW Project.  If you try to select the tool from the LabVIEW Project, you will see a menu like the one below, with only the Compare VI Hierarchies option available.


If you have ensured that you are trying to use the tool from a VI and the tools are still greyed out, ensure that you have a LabVIEW Professional Development System license. This tool is only available through the Professional Development System.

Additional Information

If you are able to see the Compare VIs option after selecting from a VI, this article contains more information on using the tool. 

Note: VIs must be loaded into memory to use the tool, and LabVIEW cannot load two VIs with the same name into memory at the same time. If the two VIs you would like to compare have the same name, you must rename one of your VIs to compare them. Renaming the VIs does not affect the name of the subVIs. If you compare two hierarchies of VIs, LabVIEW temporarily renames the top-level VI.