Terraria separates identity from environment: player characters live in .plr files and worlds live in .wld files. That makes a complete backup a two-part job. Copy both directories, including .bak companions, before editing or moving systems. Steam can independently move individual characters and worlds to cloud storage, so an apparently missing local file may have a counterpart under Steam userdata. SaveEditor.com keeps those locations distinct instead of presenting one universal Terraria save path.
Start with the least destructive explanation
When Terraria progress appears missing, first verify the active PC location: Windows: %USERPROFILE%DocumentsMy GamesTerraria
Steam cloud copies may appear under <Steam-folder>userdata<user-id>105600remoteplayers and worlds | macOS: $HOME/Library/Application Support/Terraria/ | Linux / Steam Play: $XDG_DATA_HOME/Terraria/ (normally ~/.local/share/Terraria/). Expected files/folders: Players*.plr
Worlds*.wld
*.bak. Many apparent save failures are actually profile, storefront, path-redirection, or cloud-selection problems rather than damaged game data.
Preserve every surviving copy
Back up both Players and Worlds plus their .bak files. If a character and world belong together, keep them in the same dated archive even though they are separate files. Before renaming, moving, replacing, or opening candidate backups, copy them outside the live directory. Do not use the only surviving file as the test specimen for repair or editing.
Check launcher and cloud state
Storefront context: Steam, GOG Galaxy. Steam can keep cloud-designated player/world files under its userdata remote tree. The normal local Terraria directory still separates Players and Worlds. Cloud notes: Steam Cloud and GOG Galaxy are documented. On Steam, cloud movement is enabled per character/world rather than being assumed for every local file. A sync client can reintroduce an older or newer version after a manual restore, so recovery work should keep local and cloud copies conceptually separate until the wanted progress is confirmed.
Use format and compatibility clues
Characters and worlds are separate files: .plr for players and .wld for worlds. Local .bak companions can provide rollback material. Multiplayer characters and worlds should therefore be backed up as separate sets. A world file and a player file have different structures and cannot replace one another. Cloud status can also differ per file. If the file exists but is ignored, compare the complete directory structure, slot/profile naming, game edition, mods/DLC, and any companion metadata. Do not assume an extension change or generic checksum tool can repair a game-specific container.
Game-specific troubleshooting
If a character or world is missing, check both the local directory and Steam remote location. Before using a .bak copy, preserve the current .plr/.wld and the backup so the recovery remains reversible. If a known-good backup works, preserve it and create a fresh in-game save before further experiments. If no copy works, prefer read-only inspection and source-backed game-specific tooling over repeated writes.
Verification context: Windows/macOS/Linux locations, .plr/.wld patterns, Steam remote paths, and per-item Steam cloud behavior were reviewed against current PCGamingWiki coverage.