Updated 2026-09-05

Isaac save file gone or reset: how to restore it from backups

An empty slot after an update, a Post-It without marks, three fresh files where a Dead God used to be. Before assuming the worst, look at the dated copies the game keeps on its own and at the two places a save can hide.

Where the backups are

Repentance+ writes dated copies of each slot there. The name is the date, a dot, then the normal file name: for example 20260905.persistentgamedata1.dat, or 20260419.rep+persistentgamedata1.dat when the file came from the cloud copy. Zamiell’s FAQ only says the game makes these “occasionally”; in practice one copy per slot per day of play is what people find. Repentance without the plus keeps its dated copies directly in its own folder, without a subfolder.

Restoring one

1. Close the game. Copy the whole save_backups folder somewhere else first; a bad launch can overwrite the newest copies.
2. Pick the newest copy for the slot that still had your progress. If it turns out to be bad too, try the previous day.
3. Rename the copy by removing the date and the dot, so it becomes persistentgamedata1.dat. For the cloud folder the target name is rep+persistentgamedata1.dat.
4. Put it into the active folder, the one matching SteamCloud in options.ini: Documents when the key is 0, userdata\…\250900\remote when it is 1. See the location guide.
5. Handle Steam Cloud as in the Steam Cloud guide: disable it in the game’s properties for the launch, then choose Local Save when the conflict window appears.

It is not lost, it is the other edition

Repentance and Repentance+ use separate save files. Repentance+ imports the Repentance save only on its very first launch, so progress made in Repentance later never shows up in Repentance+, and disabling the DLC shows the old files again. The transfer guide explains how to move a file across.

Last resort: Alt+F2

On the Stats screen with Secrets open, Alt+F2 syncs the file with your Steam achievements, so secrets you had earned come back. Community guides are clear about the limits: completion marks, statistics, bestiary and challenge progress are not restored, and Steam Support does not recover saves at all.

If the file is there but the game calls it corrupt, Isaac Save Editor can still open it and rewrite it with a valid checksum, which is the usual fix for a file damaged by a hex edit.