The Top-Level VI is the file that calls all the other subVIs and references, and it is not called by any other VI. To determine what is the Top-Level VI you can use the VI Hierarchy
View of LabVIEW, to find the VI that is not called by any other one. To access the VI Hierarchy open the VI you suspect could be the main VI that is within the LabVIEW Project Explorer
and go to View>>VI Hierarchy
Depending on the Application type you are developing you will find the Top-Level VI just under your computer Level if it does not involve any Real-Time Target
. Or under the Real-Time target
level if you are using a device like a CompactRIO or a PXI Controller.Under your ComputerUnder your Real-Time Target
If you open the VI Hierarchy in a SubVI
, you will find that the Top-Level VI is located above this SubVI.