Issue
By default, Windows has a 260-character path length limit (MAX_PATH).
UNC paths (like \\server\share\folder\...) count every character, so deep nested folders or long filenames push it over the limit.
Explorer drag-and-drop to Spotfire fails when paths are over the limit.
Modern software are natively build or have configurations to be aware of and allow long paths.
The above issue was verified by Spotfire Support team (refer to Case #2519650).