main's canonical default made Root::setup take std::fs::canonicalize(home), which on Windows is \\?\C:\... with the long name. root.rs now uses root::canonical (canonicalize, then the prefix off) at every site, so no root, record or message keeps the prefix; Unix is unchanged (the identity), and macOS still agrees on /tmp and /private/tmp. windows_root.rs compares against default_root(canonical(home)), so TEMP's 8.3 short name is not in the expectation, and asserts the root has no prefix. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01HS8WZziDnyxunC23MUxrLp