Oxygen Not Included can keep local and Steam-cloud colony files in neighboring but different Documents directories. That makes backup deceptively easy: copying only save_files may miss the actively synchronized colony, while copying only cloud_save_files may omit a local-only game. SaveEditor recommends preserving both trees before changing cloud settings and using timestamps plus the game build/DLC context to decide which copy is authoritative. This is safer than assuming the copy with the most familiar folder name is the newest.
Where Oxygen Not Included stores PC saves
The researched save-location boundary is Windows: Local: %USERPROFILE%DocumentsKleiOxygenNotIncludedsave_files ; Steam cloud: %USERPROFILE%DocumentsKleiOxygenNotIncludedcloud_save_files<user-id>. The known file or folder pattern is Colony save files beneath save_files or the Steam cloud_save_files account directory.. This is the practical starting point because launcher, profile, and storefront context can change which copy is active even when two folders look similar.
Storefront and profile differences
Documented launchers or storefronts: Steam, Epic Games Launcher. Do not assume save_files is the active source when Steam cloud is enabled; the user-specific cloud_save_files directory may contain the copy being synchronized. When looking for a missing save, identify the executable/storefront you actually launched and the user/profile that created the progress before copying anything between directories.
Cloud synchronization
Steam Cloud and Epic cloud are documented; OneDrive can also synchronize Documents if enabled. A cloud service should be treated as another copy of the save, not as proof that the local folder is disposable. Before a manual restore, let synchronization finish, make an offline backup, and avoid starting the game while files are being replaced.
What the files represent
Oxygen Not Included distinguishes local save_files from Steam cloud_save_files. Both live below the Klei Documents tree, so the active copy can depend on whether cloud saving is enabled for that colony. The current filename/folder evidence is Colony save files beneath save_files or the Steam cloud_save_files account directory.. File-extension context: .sav A location guide does not claim that every file in the directory is safe to edit or that files from another storefront are automatically interchangeable.
If the save is not where expected
If a restored colony is replaced, compare local versus cloud timestamps and resolve Steam/OneDrive synchronization before launching again. Avoid repeatedly overwriting both trees at once. Also check redirected Documents folders, Steam Play prefixes, account IDs, and launcher-specific containers where applicable. Preserve every candidate copy before testing a restore so troubleshooting does not destroy the only surviving version.
Verification context: Reviewed against current PCGamingWiki Oxygen Not Included save-location/cloud documentation.