MAME and Arcade Sets: Full-Set Basics for Beginners

Understand MAME versions, set types and dependencies, then use LaunchBox’s full-set importer safely with the right clone, CHD, filter, playlist, and update choices.

Written By launchbox

Last updated 6 days ago

A MAME full set is not just a folder of unrelated arcade games. It can contain parent sets, clones, shared BIOS and device ROMs, and games that need separate CHD disk images. LaunchBox has a dedicated importer that reads MAME's machine data, lets you decide what appears in your library, and points game entries at the set you already have.

Before you begin: LaunchBox and MAME do not provide commercial arcade ROMs or CHDs. Use media you are legally entitled to use, and keep a backup before changing or updating a working set.

Use the MAME full-set importer

For a complete or nearly complete MAME arcade set, open Tools > Import > MAME Arcade Full Set.... This is different from dragging thousands of ZIP files into the normal ROM importer.

The full-set importer uses data generated by the selected MAME executable to identify playable machines, parents, clones, categories, control requirements, and CHD requirements. During the import, LaunchBox creates or updates library records and downloads any media you select. It does not copy, move, rename, extract, or delete the ROM archives and CHDs in the folder you select. Game paths are recorded against that existing folder.

Match MAME to the set version

MAME's definitions change from release to release. Filenames, hashes, parent relationships, and required BIOS or device ROMs can change when better dumps are documented or emulation improves. A set from a nearby release may run many games, but compatibility can be inconsistent. The most reliable starting point is the MAME release corresponding to the set's version.

Before importing, identify:

  • The set version, usually written like 0.2xx.

  • Whether it is merged, split, or non-merged.

  • Whether you also have the matching CHD collection, if you plan to import CHD-required games.

Do not repair isolated failures by mixing random archives from different releases. That makes missing-file errors harder to diagnose and future updates harder to manage.

Understand parents, clones, BIOS sets, and device sets

MAME groups related machines using parent-and-clone relationships. The parent is the primary set definition. Clones may be regional versions, revisions, bootlegs, or variants using closely related data. A split clone can depend on files in its parent, so seeing a clone ZIP does not mean it is self-contained.

Some systems also depend on:

  • BIOS sets: shared startup or platform data, such as the BIOS used by a family of arcade hardware.

  • Device sets: ROM data for reusable hardware devices shared by otherwise unrelated machines.

These support archives may not appear as playable games in LaunchBox. Do not delete an unfamiliar ZIP merely because it is absent from the library. MAME's missing-file message or media audit can identify the parent, BIOS, device, or CHD it expected.

Merged, split, and non-merged sets

  • Merged: the parent and one or more clones are stored together in the parent's archive. This saves the most space, but clone files are not separate archives.

  • Split: the parent archive holds its normal data, while each clone archive holds only the data that differs from the parent. A clone therefore needs its parent available.

  • Non-merged: each game archive contains the ROM data needed for that game. It uses more space but makes individual games easier to separate.

The LaunchBox full-set importer supports merged, split, and non-merged sets. Keep the set in its existing form. Do not extract every archive, rename archives to friendly titles, or remove parents from a merged or split set. MAME uses short machine names and expected hashes to find data; LaunchBox supplies the friendly display names.

For more technical detail, see MAME's official About ROMs and Sets documentation.

CHD files and folder layout

Some arcade machines need one or more CHD files in addition to a ROM archive. CHD stands for Compressed Hunks of Data and is used for media such as hard disks, CD-ROMs, DVDs, and LaserDiscs. CHDs are already compressed and are best kept as CHD files rather than placed inside ZIP or 7-Zip archives.

For example, if the configured MAME ROM path is MAME\roms, a typical Area 51 layout is:

  • MAME\roms\area51.zip

  • MAME\roms\area51\area51.chd

The folder normally matches the machine's MAME short name. Some clones or delta CHDs can also depend on a parent CHD. MAME's configured rompath is the authority, so use its error output when a title cannot find a disk image. MAME explains its search rules in How MAME Looks for Files.

The LaunchBox filter Skip games that require a CHD file controls whether those games receive library entries. It does not delete, download, or repair CHDs. If CHD-required games are included, the next page can create a CHD Required playlist.

Walk through the wizard

  1. Choose the platform name. Arcade is the straightforward default. If you use another local name, the importer maps that platform to Scrape As: Arcade.

  2. Select the MAME ROM folder. Choose the folder containing the full set's machine archives, not a folder containing only CHDs. When available, select the set's Full Set Version.

  3. Choose how to handle MAME. The available choices are Automatically Install and Configure MAME (Recommended), Update MAME Emulator when a suitable existing MAME installation is detected, or Manually Configure MAME Emulator.

  4. Confirm the emulator. With manual configuration, select, add, or edit the MAME emulator LaunchBox should use. Verify its executable before continuing.

  5. Configure optional high-score leaderboards. You can enable LaunchBox community leaderboards when signed in. The wizard warns if MAME's plugins\hiscore\hiscore.dat support file cannot be found.

  6. Choose metadata and media. Select LaunchBox Games Database metadata, image types, optional EmuMovies media, and optional bezel choices. Large media selections can add substantial time and storage.

  7. Review clone, region, variant, and category filters. These determine which library entries are generated.

  8. Review control filters and generated playlists. You can exclude games requiring controls your setup lacks and choose which Arcade playlists to create.

  9. Check the Ready to Import list. This is your opportunity to go back and adjust filters before selecting Finish.

If you choose automatic installation or update, LaunchBox uses the version selected for the set and configures the LaunchBox emulator entry. If you choose manual configuration, LaunchBox leaves emulator installation to you and asks you to select an emulator entry. Emulator installation or update is separate from the ROM import: it does not convert the ROM set.

Choose how clones appear

The importer offers three mutually exclusive choices:

  • Import Clones as Additional Versions (Recommended): keeps the library compact and adds the related revisions or regions as playable versions under the main game.

  • Skip Clones Entirely: imports only the parent selection. This is the smallest library, but can omit a clone you would prefer.

  • Import All Clones as Separate Games (Not Recommended): shows each clone as its own library entry and can create a very repetitive list.

On the same page, Region to Prioritize offers North America, Europe, Japan, or World, and Variant to Prioritize offers 2-player or 4-player. These preferences help choose the primary version when related variants are grouped. They are set inside this wizard; LaunchBox's global Region Priorities option is not the control used by this MAME full-set selection.

Choose filters intentionally

The Game Types and Features filters can skip categories such as unplayable machines, hacks, prototypes, bootlegs, mechanical machines, mature titles, quiz games, fruit and casino machines, rhythm games, tabletop machines, PlayChoice titles, mahjong, non-arcade machines, and CHD-required games.

The following Controller Support section can skip machines requiring a spinner, light gun, trackball, steering wheel, two joysticks, or more than a specified number of buttons. These filters are useful for a cabinet or controller-limited setup, but they are not a statement that the underlying ROM is invalid.

All of these choices filter LaunchBox entries. They do not remove the corresponding archives from the set. Keeping a verified full set intact preserves shared dependencies and lets you change your library filters later.

Generated Arcade playlists

The wizard can create:

  • MAME subcategory playlists such as Capcom Classics or Namco Classics.

  • 2-player and 4-player playlists.

  • Genre playlists such as Beat 'em Ups or Racing Games.

  • A playlist for vertically oriented games.

  • A CHD Required playlist, when CHD-required games are included.

These are LaunchBox organization records; they do not duplicate game files. Generated playlist contents depend on the metadata and filters used during import.

Test before customizing

After import, test a small representative group before investing time in themes, artwork, or per-game controls:

  • A common parent game.

  • A regional clone or additional version.

  • A machine that uses a BIOS family.

  • A CHD-required game, if included.

  • A vertical game and a game with unusual controls.

If a game fails, launch the same MAME short name directly in the selected MAME executable. If MAME reports missing or incorrect files there, the issue is the emulator, ROM set, CHD layout, or configured ROM paths, not LaunchBox metadata. MAME's built-in media audit can also report whether required ROMs and disks are available.

Common problems

  • MAME reports missing or incorrect files: the emulator and set releases may not correspond, or a parent, BIOS, device archive, clone dependency, or CHD is missing or from a different release.

  • A CHD game closes immediately: check the CHD name, the short-name subfolder, the MAME rompath, and whether the CHD matches the set release.

  • Support archives appear as games: the normal ROM importer may have been used instead of MAME Arcade Full Set....

  • The wrong region launches first: rerun or rescan with the desired Region to Prioritize and clone mode.

  • The library is full of near-duplicates: clones were likely imported as separate games. The recommended Additional Versions mode is usually cleaner.

  • A game launches but gameplay controls are wrong: configure machine controls inside MAME. LaunchBox controller navigation and MAME gameplay inputs are separate settings.

Update a working setup safely

Treat MAME and its ROM definitions as a coordinated pair. Before an update:

  1. Back up LaunchBox's Data folder and your MAME configuration, controller mappings, high-score data, artwork, and other personal files.

  2. Record the currently working MAME and set versions.

  3. Update the emulator and the legally obtained set using the corresponding release and the instructions for your set-management workflow.

  4. Test representative parents, clones, BIOS-dependent games, and CHDs directly in MAME.

  5. Run the full-set importer again only after the new setup works, reviewing filters and the final game list before finishing.

The wizard's Update MAME Emulator choice updates a detected LaunchBox MAME installation to the version selected for the set. It does not update, rebuild, or validate the ROM set itself. Keep a recoverable copy of a working setup until the new version has passed your tests.

MAME is not FinalBurn Neo

MAME and FinalBurn Neo are separate emulator projects with different databases, supported machines, and set-version expectations. Some short names and ROM data overlap, but a FinalBurn Neo set should not be assumed to be a matching MAME set.

Use MAME Arcade Full Set... for a MAME full set. For a FinalBurn Neo collection, configure the appropriate FinalBurn Neo emulator or RetroArch core and use the standard ROM-import workflow with the FinalBurn Neo processing options offered there. Do not combine the two sets merely because some archives share names.

A safe beginner setup

Keep one intact, clearly versioned MAME set in a stable folder. Use the dedicated full-set importer, choose the corresponding MAME release, keep the recommended clone grouping unless you have a reason to change it, let filters control what appears in LaunchBox, and diagnose failures in MAME before changing library metadata.