What does this warning message mean, and how to correct it?
[Yellow Triangle] The "DataURL" parameter is controlled by a variable.
I see it at the bottom of the File Reader Configuration window.
What variable? Where is it located?
Check the flow variables tab of the node's configuration dialog. It is likely that a file path was used to embed an example data file in your workflow. If you look the the flow variable tab for the data URL option, you will be able to disable this feature by unselecting the variable from the drop down.