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.
Prepare the source PC
On the source system, identify the actual Oxygen Not Included save root: Windows: Local: %USERPROFILE%DocumentsKleiOxygenNotIncludedsave_files ; Steam cloud: %USERPROFILE%DocumentsKleiOxygenNotIncludedcloud_save_files<user-id>. The expected file/folder pattern is Colony save files beneath save_files or the Steam cloud_save_files account directory.. Close the game, let the active launcher finish writing and synchronizing, then make a complete offline copy rather than transferring a file that may still be open.
Preserve storefront and profile identity
Documented 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. A transfer between two PCs is simplest when both systems use the same storefront/account/profile context. If the destination uses a different store or container, treat that as a migration problem rather than an ordinary restore.
Move the complete save boundary
Back up both save_files and the relevant cloud_save_files user directory before changing cloud settings or moving a long-running colony. Label the copy with game build/DLC branch. Put the copied data on the destination only after confirming the destination save path. If the game creates a new empty save first, keep that new folder as another backup so you can compare structures and revert.
Handle cloud sync deliberately
Steam Cloud and Epic cloud are documented; OneDrive can also synchronize Documents if enabled. Decide whether the local transferred copy or cloud copy should be authoritative before launching the game. If possible, preserve both. After the transferred save loads correctly, make a fresh in-game save and let the launcher synchronize normally.
Check compatibility before blaming the transfer
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. Compatibility note: Save compatibility can depend on game updates and DLC branch. A local and cloud copy with the same colony name can represent different timestamps. If the destination does not see the transferred progress, 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. Verify game edition/version, store, profile IDs, redirected folders, and mod/DLC dependencies before editing the save itself.
Verification context: Reviewed against current PCGamingWiki Oxygen Not Included save-location/cloud documentation.