Solution
Most of the
File I/O VIs and Functions throw an error if the file in question is open when the VI executes. To check if a file is open, you can use a File I/O function, such as
Open/Create/Replace File, and evaluate the error code to see if the file is open. For example, Open/Create/Replace File gives error code 5 if you attempt to open a file that is already open. See the attached VI for an example.
