Error 7 When Trying to Use VI That References a Filepath

Updated Aug 9, 2022

Reported In

Hardware

  • CompactRIO Controller

Software

  • LabVIEW

Issue Details

I receive Error 7 with a message similar to the example below when I try to use a VI that is referencing a filepath:

Error 7 occurred at Open File+.vi:Open File
 
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Solution

This error occurs when the specified path does not exist. This VI will not create a path for you; for example, if the path specified is C:\Data\Today\Document1.xls and there is no Today folder in C:\Data , this error message will occur.

To resolve the issue you can:
  • Manually create the appropriate directory using your operating system's file explorer.
  • Change the specified directory within your LabVIEW program to a valid directory.
  • If the full file path already exists, ensure you are referencing the file with the correct spelling and syntax.
  • If you are reading from/writing to a file on a Real-Time target, ensure that the format of the file path matches the requirements for the Operating System. See Working with File Paths on Real-Time Targets  for more information.
  • If you are working with a Real-Time controller and you try to access a file that is located on the host computer from the Real-Time VI, you will also receive this error, since the file does not exist on the Real-Time controller. Even if the Real-Time controller is connected directly to the host, when using any VI that references a filepath, it will search on the Real-Time controller. You will need to transfer the file from the host to the Real-Time target.
  • If you are trying to access the path in the network drive from the local machine, you need to set the correct permissions for the user to access the network drive. To do this, open from the windows start menu Services >> NI Application Web Server >> Right Click and select Properties and then change the login settings for that to an account, which can access the network drive.

Additional Information

You can also programmatically create the folder if it is not found as shown below. This example is also posted as an example on the NI Developer Community.



Note: This error can occur with any File I/O VI or other function that might require a file path input and is not specific to the Read Characters From File VI.