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File Dialog Error 43 when open thousands of files

When the express File Dialog is configured to allow opening multiple files, it gives Error 43 Operation Cancelled by User if more than about 2000 files are selected.  It works fine if say 1500 files are selected.

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Message 1 of 14

Interesting. What's the actual use case for this selection?

As a workaround you may be able to do the selection mode for the entire folder and then do filtering from there.

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Message 2 of 14

Usage is to provide user selection of data files for further processing and analysis.  Files are about 60k each, 2 column ASCII Text of optical spectra from which Intensity Graph is created and other analysis performed.  The list of files is looped over and subregions extracted from each spectra and graphs of analyzed subregion data vs file number are created.

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Message 3 of 14

Which OS and LabVIEW version are you on? I want to see if I can reproduce this.


As an aside, does it really make sense to have a user multiselect 2000 files? I think a folder select with an additional text filter might be a better design.

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Message 4 of 14

I did a test with LabVIEW 2011 and Windows 7 with 4000 empty files and didn't have any problems so it's not a file number limitation.

Makes me think it must be a memory limitation of some sort.


I'll try with non-empty files and see if I can break it.


How much RAM do you have on your system?


EDIT: Also tried with 2000 64KB files and had no problems.

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Message 5 of 14

Windows 7 64 bit with LabVIEW 2012 SP1 f5 32 bit.


File size doesn't matter as the files are not opened yet when this error happens.


A VI containing only the express FIle Dialog with Selection Mode configured to not Limit Selection to Single Item will give this error for me.  File Dialog's "selected paths" is not wired to anything.

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Message 6 of 14

Did you solve the problem? We are experiencing exactly the same, but with as few as 227 files. From the 228th file on, the string indicator in the dialog gets blank and upon clicking "ok" the dialog returns an empty array and throws error 43.

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Message 7 of 14

NI R&D is aware of the bug and a Corrective Action Request (Req # 484053) has been filed to resolve this issue. 


The current suggested workaround is to call the File Dialog Express VI multiple times, and build up the file path array yourself.


Feel free to contact our Applications Engineering Team to check whether a permanent solution has been reached.



Applications Engineering

National Instruments


Applications Engineering
National Instruments
Message 8 of 14

It has been 2.5 years since this you indicated that "NI R&D is aware of the bug and a Corrective Action Request (Req # 484053)".  This bug has not been fixed yet.  Any word on when you are going to get around to actually fixing it?

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Message 9 of 14

For me the limit is 1817 files

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Message 10 of 14