Configuration Data Storage

Data Storage

FindRomCover keeps configuration, caches, and logs in a per-user data folder; the MAME database ships next to the executable.

Data folder

Platform	Location
Windows	%LocalAppData%\FindRomCover (typically C:\Users\<you>\AppData\Local\FindRomCover)
Linux	~/.local/share/FindRomCover
macOS	~/Library/Application Support/FindRomCover

The application creates the folder on first start. Writable data is kept here because the installation folder is not writable for typical setups.

Files

File	Format	Purpose	Retention
Settings.dat	SQLite	All settings, including encrypted API keys	Until deleted
QueryHistory.dat	SQLite	Covers already queried with AI Assist	180 days, max 100,000 entries
QueryHistory.dat.corrupt	SQLite	Quarantined query-history database that could not be read	Until deleted
ai-cache.json	JSON	Cached AI verdicts	30 days, max 2,000 entries
ai-models.json	JSON	Cached model lists per provider and base URL	7 days
app<yyyyMMdd>.log	Text	Rolling daily application log	7 files
ApiLogError.txt	Text	Reports queued for the bug-report API; an accepted report is removed after a successful send	Until the send succeeds
UserLogError.txt	Text	Simplified error list for user reference	Until deleted
InternalLog.txt	Text	Internal error-logger diagnostics	Until deleted
Settings.dat.corrupt	Any	Quarantined settings database that could not be read	Until deleted
settings.dat.legacy	Encrypted legacy file	Backup of a pre-SQLite settings file	Until deleted
Screenshot\Screenshot_<timestamp>.png	PNG	Screenshots saved with F8 when the application folder is not writable	Until deleted

Note: settings.dat.legacy may appear in the data folder or next to the executable, depending on where the legacy file was found. Settings.dat.corrupt is created in the folder that held the unreadable file.

Application folder

These files live next to the FindRomCover executable:

File	Purpose
mame.dat	MAME game database used for descriptions
settings.dat.legacy	Legacy settings backup after migration (if migrated from the application folder)
settings.dat.corrupt	Quarantined legacy settings file that could not be read
settings.xml.migrated	Legacy settings.xml moved aside after a successful migration

Settings database

Settings.dat is a SQLite database with a simple key/value table:

CREATE TABLE Settings (
    Key   TEXT PRIMARY KEY,
    Value TEXT NOT NULL
);

Every setting is stored under its property name, for example BaseTheme, SimilarityThreshold, AiProvider, AiModel. List values such as SupportedExtensions are stored as JSON arrays.

Encryption

Sensitive values are encrypted with AES using a PBKDF2 key derived from Environment.MachineName plus a constant application salt and password:

• GoogleKey
• AiApiKey
• BugReportApiKey

The key is not tied to the user account. Copying Settings.dat to another user account on the same machine still decrypts the secrets, because the machine name is unchanged. Copying it to another machine does not: the derived key differs, the secrets cannot be decrypted, and they must be entered again. All other values are stored in clear text inside the database; the database itself is not encrypted.

Migration from older versions

When FindRomCover starts and the settings database is not a SQLite database, it assumes the legacy encrypted settings.dat format and:

1. decrypts the file;
2. applies every setting it contains, including API keys;
3. writes the settings to the new SQLite database;
4. renames the old file to settings.dat.legacy as a backup.

The same migration runs for a legacy settings.xml, which is moved to settings.xml.migrated after a successful conversion. Legacy files may be found in the data folder or next to the executable. If a legacy file cannot be decrypted, it is preserved as a .legacy backup and defaults are used instead. If a SQLite database is corrupt, it is renamed to Settings.dat.corrupt and defaults are restored.

Query history database

QueryHistory.dat uses non-pooled SQLite connections, so the file is never held open:

CREATE TABLE QueryHistory (
    TargetPath TEXT PRIMARY KEY COLLATE NOCASE,
    QueriedUtc TEXT NOT NULL,
    Outcome    TEXT NOT NULL
);

Entries older than 180 days are removed, and the table is trimmed to 100,000 rows when it grows beyond that. If the file cannot be read as SQLite, it is quarantined as QueryHistory.dat.corrupt and a fresh database is created. See Query History.

Caches

Cache	Key	What is stored
ai-cache.json	Game and candidate set	AI verdicts, including confidence and choice
ai-models.json	Provider and base URL	The list of models returned by the provider

Both caches are best-effort: deleting them only means the next request is slower or costs a little more.

Backing up and restoring

Backup

1. Close FindRomCover.
2. Copy the whole per-user data folder.

Restore

1. Close FindRomCover.
2. Replace the folder with your backup.
3. Start FindRomCover.

Caution: Settings encryption is tied to the machine name, not to the user account. A settings database copied to another user account on the same machine still decrypts; on another machine it does not, and API keys must be entered again.

Cleaning up

Goal	Action
Free space	Delete ai-cache.json and ai-models.json
Reset query history	Use Clear query history in AI Settings, or delete QueryHistory.dat
Full reset	Delete Settings.dat (also removes stored API keys)
Remove legacy backups	Delete settings.dat.legacy, settings.dat.corrupt, settings.xml.migrated, and QueryHistory.dat.corrupt

Related pages

• Settings Overview
• Query History
• Logs & Diagnostics
• Bug Reports