Hollow Knight provides four clear profile files and also creates useful backup copies, making it a strong candidate for careful manual recovery. The key is to keep the entire LocalLow folder rather than only user1.dat: each slot can have a .bak file, older-version backups may appear after patches, and some global preferences/unlocks live elsewhere. SaveEditor therefore describes both the slot files and the boundary of what they do not contain, which avoids misleading a user who restores progress but still sees old global settings.
Known Hollow Knight save-file structure
The researched filename or folder pattern is user1.dat through user4.dat; user#.dat.bak1 backup files and older-version copies may also exist.. File-extension context: .dat, .bak The documented format notes are: The four player profiles are individual user#.dat files. The game also keeps automatic backup/older-version files, while some unlock/preferences data lives outside the main save files.
Why an extension is not enough
A save filename can identify a likely container, but it does not prove the internal schema, game version, checksum rules, encryption state, or editability. A profile file is not the whole application state. Steel Soul/Godseeker-style unlocks and settings can be stored outside the slot file, so slot restoration may not reproduce or erase those flags. SaveEditor therefore separates file identification from Tool compatibility and only labels a game-specific Tool Verified when its exact profile/version evidence passes the runtime gate.
Where the format is stored
PC save locations: Windows: %USERPROFILE%AppDataLocalLowTeam CherryHollow Knight ; Microsoft Store progress can also involve the package WGS area documented by PCGamingWiki.. Storefront context: Steam, GOG, Microsoft Store. The main Windows profile files are under LocalLow. Some preferences/unlocks are stored separately, so replacing user1.dat does not necessarily reset every game-wide flag. This matters because two releases can use different containers or companion files even when the visible slot name is similar.
Back up before inspecting or editing
Back up the entire Hollow Knight LocalLow directory, not only one user#.dat. Keep the corresponding .bak files so the game-created recovery copies remain available. A read-only viewer is lower risk than a writer, but the live save should still be copied first. Cloud context also matters: Steam Cloud, GOG Galaxy, and Xbox Cloud are documented. Keep the original bytes available so any experiment can be reversed without relying on a cloud service or automatic backup.
What this reference does not claim
This page does not infer an undocumented checksum algorithm, encryption key, compression layer, or cross-store conversion from the file extension. Troubleshooting evidence: If a profile is corrupt or missing, try the matching game-created .bak only on a copy and preserve the current directory first. Verify the slot number before renaming files. Those questions require a verified parser/profile or a game-specific source, not a generic format guess.
Verification context: Reviewed against current PCGamingWiki Hollow Knight data plus the Hollow Knight Wiki Save Data page for user#.dat and .bak naming.