Close File VI Error Message: " An input parameter is invalid.

[Paul J S]

Problem Description :
I'm modifying an existing Labview project that had been working fine until I made a slight change. I'm getting following error:
"LabVIEW: An input parameter is invalid. NI-488: Command requires GPIB Controller to be Controller in Charge."
This occurs when code reaches Close File VI. The program use to end at this
point without complaint until I modified the program and added a while loop
outside the original routine.
Any clues I can start looking for?
Paul

[jmcbee]

Are you sure the error occurs at Close File VI?  You should put your code in highlight execution mode (the light bulb on the block diagram) and watch your error cluster wire, it will show the error in red text when it occurs, this info may help to pinpoint the issue.

[Dennis Knutson]

You are also missing part of the error message. It says possible reason(s) and you should concentrate on possible reason 1 - "An input parameter is invalid. For example if the input is a path, the path might contain a character not allowed by the OS such as ? or @." Some of these old error codes are shared between LabVIEW and GPIB errors.
Make sure that nothing before the close file is actually causing an error and since the close file has only a single input (reference), make sure that the reference is correct. If you have things in a loop now, the number of times you open files has to match the number of times you close files.

[Wise Owl]

I just had a similar error while creating an Executable file.  The build would halt half way through with the same error.  I "fixed" the problem with running the vi that contained the Close File vi and then saving it.  Perhaps this forced LabVIEW to recompile and then recognise the correct inputs...? Damian