The following bug has been logged on the website:
Bug reference: 15858
Logged by: William Allen
Email address: williamedwinallen(at)live(dot)com
PostgreSQL version: 11.3
Operating system: Windows Server 2012 R2
Description:
Issue using copy from command for files over 4GB.
ERROR: could not stat file "E:\file.txt": Unknown error
SQL state: XX000