For followers of this thread:
Windows 10 now handles long file paths although it has to be enabled with via various possible registry or group policy edits. However, LabVIEW apparently has not opted in as of LV 2019 SP1.
I made a post on the LV idea exchange to make long file paths work in LV.
Separately from the OS limitation, LabVIEW cannot handle more than 255 chars per element of a path. That’s quite uncommon, but can happen when file or folder names are generated programmatically.
"LabVIEW cannot handle more than 255 chars per element of a path"
If you run into that issue i'd say you have some other problems! 😄
I've always used the File Dialog Express VI to navigate to the file then open it using the Open/Create/Replace VI but have never ran into the 255 character limit. I wonder if that would work and bypass the character limit set by NI.