Thank you. Your response makes sense and allowed me to determine that a GPO lockdown policy was prohibiting access to the directory path that was stored in the LastPath registry setting.

Users were launching the application and manually changing the explorer path after connection.

WinSCP looks for any path that it can open in the local file panel.
So I do not think that WinSCP can be fully functional after you dismiss the error.
Or is it? Does it open some sensible path in the local panel despite the error? Can you post a screenshot?

What you can do is to navigate the local panel to some valid path. It probably has to be an UNC path, as you system does not seem to have any local drive. WinSCP should remember that and start of that path the next time, without any error.

If you do not actually use the local panel, you can switch to Explorer interface:
https://winscp.net/eng/docs/interfaces
https://winscp.net/eng/docs/ui_explorer

Operating System: Windows Server 2019

WinSCP v5.21.1 has been installed on a Citrix 1912 master image. When the images are provisioned (effectively cloned), the cloned VMs receive the error message

Can't find any valid path.

When the users click "OK" WinSCP loads up fine and is fully functional.
I'm looking to eliminate the error message.

Research:
https://github.com/Rupan/winscp/blob/master/source/WinSCP.drc shows that "Can't find any valid path." error message may originate from Baseutils_SNoValidPath, "Can't find any valid path."

Any thoughts on what path is being searched for at application launch?

Thanks