If a VI does not run, it is a broken, or nonexecutable, VI. The Run button appears broken, shown as follows, when the VI you are creating or editing contains errors.
If the button still appears broken when you finish wiring the block diagram, the VI is broken and cannot run.
Warnings do not prevent you from running a VI. They are designed to help you avoid potential problems in VIs. Errors, however, can break a VI. You must resolve any errors before you can run the VI.
Click the broken Run button or select View»Error List to find out why a VI is broken. The Error list window lists all the errors. The Items with errors section lists the names of all items in memory, such as VIs and project libraries that have errors. If two or more items have the same name, this section shows the specific application instance for each item. The errors and warnings section lists the errors and warnings for the VI you select in the Items with errors section. The Details section describes the errors and in some cases recommends how to correct the errors. Click the Help button to display a topic in the LabVIEW Help that describes the error in detail and includes step-by-step instructions for correcting the error.
Click the Show Error button or double-click the error description to highlight the area on the block diagram or front panel that contains the error.
The toolbar includes the Warning button, shown as follows, if a VI includes a warning and you placed a checkmark in the Show Warnings checkbox in the Error list window.
Configure LabVIEW to always show warnings in the Error list window by selecting Tools»Options, selecting Environment from the Category list, and placing a checkmark in the Show warnings in Error List dialog by default checkbox in the Debugging section. You can make this change with the Error list window open and see the change immediately.
The following list contains common reasons why a VI is broken while you edit it: