1. Update before trying a recovery trick
Patch 9.0.72 added a backup-save fallback, 9.0.78 added corruption guards, and 9.0.901 fixed a null-reference error that prevented some saves from loading. Patch 9.0.97 moved game backups outside the Steam Cloud folder and fixed a controller new-game Load button that could overwrite a save slot. Let Steam finish patch 9.0.97 or newer, fully close the client, reopen it and launch once before changing anything else.
2. Protect both local and Cloud copies
Steam lists Cloud support for Stackmon. Patch 9.0.97 says game backups are now stored outside the Steam Cloud folder, but does not publish a manual restore path. If Steam presents a sync-conflict prompt, compare timestamps carefully and do not overwrite one copy with another. Preserve local, Cloud and game-backup copies until the correct progress is visible.
3. Verify the installed game files
In the Steam Library, open Stackmon Properties, choose Installed Files and run “Verify integrity of game files.” This checks the installation before you blame the save itself. Restart Steam after verification, then test one normal launch. Avoid reinstalling, deleting folders or using a third-party cleaner as the first response.
4. Identify which problem you actually have
A crash before the main menu, a save that refuses to open, a save that opens with missing Stackpedia entries and a Steam Cloud conflict are different failures. Write down the exact screen, error text and last successful action. If the game opens normally but only collection entries are missing, say that clearly instead of reporting the whole save as lost.
- Crash before reaching the save list
- Save appears but fails during loading
- Save opens and world progress is present, but Stackpedia entries are missing
- Steam asks you to choose between local and Cloud data
5. Send a report the developer can act on
Patch 9.0.81 added a save-error report system, and Riftpoint asks players with remaining save problems to send the report and save through the official Discord. Include the current patch number, operating system, whether Steam Cloud was enabled, the last action before the problem, the exact loading behavior and whether world progress or only Stackpedia progress is missing. Keep the original file untouched while sharing a copy.
6. Keep Demo saves out of the retail recovery path
The retired Demo used a different save structure, and its progress does not transfer to the full game. Do not rename or copy a Demo save into the retail location in an attempt to restore progress. That mixes two separate problems and can make the current retail state harder to diagnose.
Stop before a destructive step
If updating, one clean relaunch and file verification do not help, preserve the current state and wait for game-specific advice. A manual replacement guide is only safe when the developer publishes the expected files and recovery order. Until then, keeping every copy is more valuable than trying a generic save-repair recipe.