Error 5: “LabVIEW: File already open” when Writing, Deleting or Replacing File

Issue Details

• I am trying to use File I/O VIs in LabVIEW to write to, delete or replace a file, but when I run the code, a VI returns Error 5 – “LabVIEW: File already open”. What can I do to resolve this issue?
• I am trying to use the Report Generation Toolkit in LabVIEW, but I keep receiving Error 5. How can I fix this?

Solution

• If you have another application that is reserving your file (like backup applications, NI DataFinder, or desktop search applications):
  • Add error handling to retry the file operation when Error 5 occurs.
  • Disable the offending application.
• If you are trying to perform multiple, simultaneous file writes on the same file within your LabVIEW VI either:
  • Serialize the operation.
  • Use an asynchronous File I/O API (like the TDMS Advanced API)
• If using the Application Builder:
  • Try cleaning the build directory and then rebuilding your application. In the project, right-click on Build Specification»Clean.
  • Try changing the location of the build directory.

Additional Information

Error 5 is not guaranteed to be thrown in the event that a file is already open and should not be relied upon as a method of preventing race conditions or as a method of controlling file access.