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.
Choose the correct backup boundary
For RimWorld, the researched PC save location is Windows: %USERPROFILE%AppDataLocalLowLudeon StudiosRimWorld by Ludeon StudiosSaves. The known save file or folder pattern is *.rws; manual names plus Autosave-* records.. Back up the entire Saves folder and also record the RimWorld version, DLC set, and mod list/load order that produced an important colony. Copying the complete documented save boundary is safer than selecting one visually obvious file, because companion metadata, indexes, backups, or multiple slots can be required together.
Make an offline copy before changing anything
Close the game first, wait for the active launcher to finish writing, then copy the save data to a separate folder that the game and sync client do not watch. Label the copy with the game, storefront, profile, and date. Documented launcher context: 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.
Account for cloud saves
Steam Cloud is commonly used; the official/community wiki documents platform-specific save directories. Before restoring an older backup, decide which copy should win. If the game or launcher starts while an older manual copy is in place, synchronization can replace it before you confirm that it works. Keep the untouched backup outside the live save path until the restored progress has been opened and saved normally.
Restore without changing format assumptions
RimWorld saves are XML-based .rws files and embed world/colony state plus references to active DLC/mod content. The game can show the save-data location from its settings UI. Compatibility note: 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. Restore into the matching storefront/profile context whenever possible. Do not rename a save extension, move a folder into a different container type, or assume a console/mobile copy is equivalent unless a tested migration path specifically says so.
Recovery fallback
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. If the restored copy fails, put the untouched original back first. Then compare location, account/profile, cloud state, and the full directory structure before trying a different backup. The objective is reversible recovery, not repeated destructive experiments on the only copy.
Verification context: Reviewed against the current RimWorld Wiki Save file documentation and current PC save-location conventions.