Using Multiple Emulators for One Platform: Defaults, Launch With, and Per-Game Overrides

LaunchBox can keep several emulators available for one platform. For example, most PlayStation games might use DuckStation while a few use RetroArch, or one RetroArch core might be the everyday choice while another is kept for compatibility testing.

The safest setup is to separate three ideas:

• Associated Platforms says which local platforms an emulator is configured to launch and stores platform-specific launch settings.

• Default Emulator identifies the normal emulator, or RetroArch core row, for a platform.

• A game's emulator is the emulator entry saved on that individual game.

Add a second emulator

1. Open Tools > Manage > Emulators...

2. Choose Add, or select an existing entry and choose Edit.

3. On Details, confirm the emulator name and Emulator Application Path.

4. Open Associated Platforms.

5. Add a row for the platform, configure the row, and save the emulator.

The value in Associated Platform is your local LaunchBox platform name. Select it from the list when possible. Although parts of LaunchBox can recognize equivalent database platform names, an exact local name is the most dependable choice and is required for the emulator to appear in the Desktop Launch With list.

What the Associated Platforms columns mean

The grid contains the following settings:

• Associated Platform: the local LaunchBox platform this row handles.

• Core: shown for RetroArch entries. It selects a core DLL found in that RetroArch installation's cores folder.

• Default Command-Line Parameters: the normal platform-specific command line for a standalone emulator.

• Extra Command-Line Parameters: shown instead for RetroArch because LaunchBox builds the core argument separately.

• Default Emulator: makes this emulator and row the normal choice for the platform.

• Extract ROMs: extracts supported archives to LaunchBox's temporary extraction area before launching.

• Use M3U Playlists for Multiple Discs: allows LaunchBox to create and launch an M3U for eligible multi-disc games.

• Status: shown for RetroArch and reports core availability; a missing-core status can be used to obtain the core.

Extract ROMs and Use M3U Playlists for Multiple Discs belong to each association row. Configure them for the actual emulator or core being tested rather than assuming every emulator supports the same input.

Choose the platform default

Check Default Emulator on the row you want LaunchBox to prefer. There can be only one default association for a platform. If another emulator is already the default, LaunchBox asks whether to replace it.

Saving a newly selected default has two possible effects on existing records:

• Games and emulated Additional Apps on that platform that do not have an emulator assigned are automatically assigned the new default.

• If games or emulated Additional Apps already point to another emulator, LaunchBox asks whether you want to change them to the new default. The prompt defaults to No.

New game creation and import workflows can select the platform's default emulator. An import wizard may also let you explicitly choose another emulator; review the emulator page and final import list rather than assuming the current default will always be used.

Test an alternative with Launch With

1. Right-click a game that already uses an emulator.

2. Open Launch With.

3. Select an associated standalone emulator, or expand a RetroArch entry and select a core.

Launch With is a one-launch override. It launches the selected emulator or RetroArch association, but it does not save that choice on the game and does not change the platform default. Normal play continues to use the game's saved emulator afterward.

An emulator is offered here when it has an Associated Platforms row matching the game's local platform. A RetroArch submenu lists its matching rows that contain a core/command line, with the default row ordered first. The menu can include the emulator the game already uses as well as alternatives.

Appearing in the menu means the association exists; it does not prove that the emulator supports the game's file format, BIOS, controller configuration, or disc structure.

Make a standalone emulator permanent for one game

1. Right-click the game and choose Edit.

2. Open the Emulation page.

3. Enable Use an Emulator.

4. Under Choose an Emulator, select the alternate entry.

5. Save and test the game.

The chooser lists all configured emulator entries, not only those associated with the current platform. Therefore, selecting an emulator here does not replace proper Associated Platforms setup. Add the platform row so that LaunchBox can find its platform command line, extraction and M3U settings, and so the emulator appears under Launch With.

A game's stored emulator is an explicit selection. Later changing the platform default does not silently replace it unless you accept the reassignment prompt when saving a new default.

RetroArch: one entry can contain several cores

A single RetroArch emulator entry can contain more than one Associated Platforms row for the same platform, provided the rows use different cores or command lines. Only one of those rows can be marked Default Emulator. This is useful for presenting several cores under Launch With.

There is an important limitation: a game stores the RetroArch emulator ID, not a particular Associated Platforms row. Normal play therefore uses the default matching row. Selecting the same RetroArch entry on a game's Emulation page does not permanently select its second core.

For a permanent per-game alternate core, the clearest beginner setup is:

1. Create a second LaunchBox emulator entry pointing to the same retroarch.exe.

2. Name it for the alternate core, such as RetroArch - SwanStation.

3. Associate it with the platform and select that core.

4. Leave this alternate row unchecked under Default Emulator.

5. Test it with Launch With, then select that emulator entry on the affected game's Emulation page.

Advanced users can instead give a game a complete custom RetroArch command line, but the separate-entry approach is easier to understand, bulk-edit, and reverse. Confirm that the selected core DLL remains installed in that RetroArch entry's cores folder.

Understand custom command-line precedence

For a normal launch, LaunchBox chooses parameters in this order:

1. A command line explicitly supplied by Launch With.

2. The saved game's custom command line from Use Custom Command-Line Parameters.

3. The selected emulator's matching Associated Platforms row, with a default matching row preferred.

4. The emulator-wide default command line when no matching row supplies one.

When only one game fails, first check its custom parameters. When every game using an association fails, check the emulator path, associated platform row, core, BIOS, and default parameters.

Bulk-change selected games

1. Select the games.

2. Press Ctrl+E or open the Bulk Edit Wizard.

3. Choose the Emulator field.

4. Select the replacement and complete the wizard.

The emulator list is not filtered by platform, so select carefully. Bulk Edit replaces the emulator ID on every selected game. It also updates a related Additional App when that app uses an emulator and its emulator ID matched the game's old emulator ID. It does not blindly overwrite every related app; apps with a different explicit emulator or apps that do not use an emulator are left alone.

Changing a game's platform is a separate operation

In the single-game editor, changing Platform to one with a configured default selects that new default emulator. If the emulator changes, LaunchBox clears the game's custom emulator command line; it also turns off the dedicated DOSBox or ScummVM mode when switching to standard emulation.

By contrast, Bulk Edit's Platform field changes only the platform value. It does not change the selected emulator. After a bulk platform move, verify the Emulator field and make sure that emulator has an Associated Platforms row for the destination platform.

Additional Apps and combined versions

Emulated Additional Apps, including entries used as additional versions, can store their own Use Emulator setting, emulator ID, application path, and command line. Changing only the primary game's emulator does not automatically rewrite every related entry.

There are two intentional propagation cases:

• When saving a new platform default, LaunchBox assigns it to unassigned emulated Additional Apps and can prompt to replace existing assignments.

• When using Bulk Edit's Emulator field, an emulated Additional App follows the change only when it was using the same old emulator as its parent game.

Review alternate versions, discs, setup utilities, and other Additional Apps after a platform-wide change. Some should continue to launch directly and should not have Use Emulator enabled.

File formats, extraction, BIOS, and firmware

Two emulators associated with the same platform can support different content. Check each emulator for:

• ZIP and 7Z support, or whether Extract ROMs is needed.

• CUE/BIN, CHD, RVZ, CSO, M3U, folder-based games, and other formats.

• BIOS or firmware filenames, regions, checksums, and directory locations.

• Encrypted images, keys, or other emulator-specific requirements.

Test the alternative emulator directly when necessary. A game working with one emulator does not prove that another has the same dependencies or file support.

Protect saves and controls before switching

Standalone emulators and RetroArch cores may use different save folders, memory-card layouts, filenames, and formats. Save states are especially sensitive to the emulator, core, and version.

1. Create an in-game save when possible.

2. Back up save, memory-card, and state folders.

3. Record the old emulator, core, and version.

4. Verify compatibility or conversion guidance from the emulator project's documentation.

5. Keep the old emulator and files until progress is confirmed in the replacement.

Also retest controller mappings, fullscreen behavior, pause screens, hotkeys, disc swapping, save/load, and exit-to-LaunchBox behavior. These can differ even when the game itself launches successfully.

Remove an emulator safely

Deleting an emulator entry from Tools > Manage > Emulators... removes that LaunchBox configuration after confirmation. It does not first migrate games that reference it. Those games can retain an invalid emulator ID and fail with an “emulator no longer exists” error.

1. Bulk-assign games that use the old emulator to a tested replacement.

2. Review emulated Additional Apps and versions.

3. Make another association the default for every affected platform.

4. Back up emulator saves and configuration.

5. Delete the LaunchBox emulator entry only after testing.

Deleting the LaunchBox entry does not by itself delete the emulator's installation folder. Keep that folder until saves, settings, and the replacement setup have been verified.

Common problems

• Launch With is missing or disabled: the game must already use an emulator, and alternatives need an exact Associated Platform row for the game's local platform.

• An emulator is absent from Launch With: correct or add its Associated Platforms row.

• A RetroArch entry appears but has no usable core choices: give its matching platform rows valid cores/command lines and confirm the DLLs exist.

• Launch With works, but normal Play uses another emulator: Launch With does not persist; edit the game's Emulation page.

• Normal Play uses the wrong RetroArch core: check which same-platform row is marked Default Emulator, or use a separate RetroArch emulator entry for a permanent exception.

• Only one game fails: disable or correct its full custom command line.

• The emulator opens without the game: check its parameters, ROM placeholders, file-format support, extraction setting, and application path.

• Saves appear missing: compare the old and new emulator's save directories and game identifiers; do not delete either copy.

Recommended workflow

1. Keep the currently working emulator as the default.

2. Add and fully configure the alternative, including its Associated Platforms row.

3. Use Launch With to test a representative game.

4. Back up saves for games with existing progress.

5. For a permanent alternate RetroArch core, create a clearly named second emulator entry.

6. Assign the alternative only to games that need it.

7. Retest input, saves, pause, disc handling, and exit behavior.

8. Keep the old setup available until the replacement is proven.