Why is a Red Outline Around my Block Diagram

Updated Aug 22, 2023

Reported In


  • LabVIEW Base
  • LabVIEW Full
  • LabVIEW Professional

Issue Details

My block diagram has a red outline. What does this mean and how can I remove it?


The red line signifies a breakpoint on your block diagram.  To remove the breakpoint, open the tools palette by selecting View»Tools Palette or holding Shift+right-click on the Block Diagram.  Then select Tools Palette»Breakpoint Tool and left-click on any empty space in your block diagram.  The red outline and corresponding breakpoint will disappear.

Additional Information

A breakpoint is one of the tools that you can use to debug your LabVIEW VI. Normally, you would use this tool on a wire to pause the execution of your VI at a particular point, but it is very easy to accidentally click the block diagram itself, instead of a wire.

If this happens, a red outline will appear around your block diagram, and this will effectively pause your VI before anything on your block diagram executes. This is helpful, if you want to step through your VI while debugging, but it can make your VI behave strangely when you try to run it normally.