A file or folder with the name … already exists
This message shows up in 2 different situations. Pick the one that matches yours:
- A # or % in a file or folder name — the classic …Url APIs cannot reach it, and the old writes quietly save %25The classic …ServerRelativeUrl lookups, Files/add(url=), folders/add, moveto and copyto cannot reach it even encoded: 404/400, Exists: false for a folder that exists, and writes that answer 200 but save a literal %25; ResourcePath API with the path doubled and URL-encoded, plus its different answers on an existing target (measured)Cause and fix →
- Dropping a folder onto your upload zone does nothing (dataTransfer.files never sees it)dataTransfer.files cannot see a folder, items is neutered after the first await, and readEntries() returns the contents in batches of 100Cause and fix →