Case and Unicode conflicts: when identical-looking names collide and get renamed

Dropbox's server namespace is case-sensitive and tolerant of different Unicode encodings, but the Windows and macOS filesystems it syncs to are case-insensitive and normalize names differently. That mismatch produces two recurring classes of conflict.

A case conflict occurs when two items differ only in capitalization — for example a folder named 'records' and another named 'Records'. This is perfectly legal on dropbox.com but impossible on a case-insensitive local filesystem, so when the files sync down, Dropbox appends '(Case Conflict)' to one of them. A Unicode encoding conflict occurs when two names look identical on screen but differ in their underlying Unicode byte representation (such as composed NFC versus decomposed NFD forms of accented characters); these collide on a local filesystem that normalizes them to the same thing, and Dropbox appends '(Unicode Encoding Conflict)' to one.

In both cases Dropbox silently renames a file to avoid losing it. The renamed file is preserved, but its name no longer matches what the user or their software expects.