RimWorld makes the file format comparatively transparent—.rws saves are XML—but that does not make them context-free. A colony serializes references to the game version, DLC, mods, world objects, pawns, maps, and many definitions supplied by the active content set. SaveEditor therefore treats a proper backup as the .rws file plus environment notes. This is especially important before removing a mod or upgrading a heavily modded colony, because an XML parser succeeding does not prove that RimWorld can reconstruct every referenced definition.
Which storefront context matters
Documented RimWorld PC launchers/storefronts: Steam, GOG, Epic Games Launcher. The save file is human-readable XML, but it is highly version/mod dependent. Editing XML without understanding cross-references can create a loadable-looking file that fails later. The active storefront/account should be identified before any restore because cloud and local storage may not use the same path or container across editions.
Documented cloud behavior
Steam Cloud is commonly used; the official/community wiki documents platform-specific save directories. Cloud synchronization is useful for continuity, but it can also turn a restore into a conflict-resolution event. Let synchronization settle before making a manual backup, and keep an offline copy outside any folder monitored by the launcher or operating-system sync service.
Local save roots still matter
The researched local save boundary is Windows: %USERPROFILE%AppDataLocalLowLudeon StudiosRimWorld by Ludeon StudiosSaves; the known file or folder pattern is *.rws; manual names plus Autosave-* records.. A cloud-enabled game still has concrete local data involved in ordinary play, and that local context is what you need when identifying which copy was modified most recently.
Avoid accidental overwrite loops
Back up the entire Saves folder and also record the RimWorld version, DLC set, and mod list/load order that produced an important colony. When restoring, close the game and launcher, preserve both the current local copy and the backup you want to test, then place the intended data in the matching profile/storefront location. Do not repeatedly open the game between different copies without noting which side the cloud client selected.
Compatibility and conflict checks
A .rws file can be structurally valid XML yet incompatible with a different mod set or game version. Missing definitions are a compatibility problem, not automatically file corruption. If progress disappears or rolls back, If a colony fails after an update or mod change, restore the save and matching mod environment together. Use the in-game “Show” save-data-location action when uncertain about the active folder. Resolve identity/path/cloud questions first. A cloud conflict is not proof that the save itself is corrupt, and a successful upload is not proof that files from another storefront are compatible.
Verification context: Reviewed against the current RimWorld Wiki Save file documentation and current PC save-location conventions.