Sorting your collection is not a luxury: dumping groups regularly publish corrected versions that remove bugs or improve how a game behaves under emulation. An outdated rom means a game that crashes — and in netplay, a session that cannot even start.
You need three things: a piece of software, a reference .dat file and, for a few systems, a header file.
If you are just starting out, begin with Romulus: its interface is far more approachable.
Recalbox has dedicated pages for clrMamePro and Romulus.
.dat filesA .dat file is a system's reference catalogue: it lists every known game with its signature. Your software compares your folder against that catalogue and tells you what is correct, broken or missing.
The .dat files matching exactly the cores shipped with your version of Recalbox are installed on the machine and reachable over the network share, in the arcade folder:
┣ 📁 recalbox
┃ ┣ 📁 share
┃ ┃ ┣ 📁 arcade
┃ ┃ ┃ ┣ 📁 advancemame
┃ ┃ ┃ ┃ ┣ 🗒 advancemame.dat
┃ ┃ ┃ ┣ 📁 libretro
┃ ┃ ┃ ┃ ┣ 🗒 fbneo.dat
┃ ┃ ┃ ┃ ┣ 🗒 mame0278.dat
┃ ┃ ┃ ┃ ┣ 🗒 mame2003-plus.dat
┃ ┃ ┃ ┃ ┣ 🗒 …
┃ ┃ ┃ ┃ ┣ 📁 fbneo-non-arcade
┃ ┃ ┃ ┣ 📁 supermodel
┃ ┃ ┃ ┃ ┣ 🗒 supermodel.dat
Under libretro/ you will find, among others: fbneo.dat, mame0258.dat, mame0278.dat, mame2000.dat, mame2003.dat, mame2003-plus.dat, mame2010.dat, mame2015.dat, dice.dat, mednafen-stv.dat, plus the Naomi, Naomi 2, Naomi GD and Atomiswave dats (the -next variants belong to the Flycast Next core). The Neo-Geo dat and FinalBurn Neo's "console" dats live in the fbneo-non-arcade subfolder. AdvanceMAME, piFBA and Supermodel each have their own folder.
Available cores vary from one machine to another: the files present in this folder are your Recalbox's — that is the only list that matters for you.
This folder is only visible over a network share (
arcade) or through SSH — it does not appear in the systems list.
Download the .dat file matching the group you picked (see Which romsets to use with Recalbox):
Mixing one group's romset with another group's .dat never ends well: always take the dat of the group your set comes from.
For a few systems, your software will also ask for a header file alongside the .dat:
An international selection looks like this:
Some RetroAchievements only unlock with the USA rom, and some games only exist in Japanese. If you chase achievements, keep those versions alongside your own.
Depending on the region, the same game can differ noticeably: a different boss, a different blood colour (red in the USA version, green in the European one), a different frame rate and machine frequency (50 Hz on PAL versus 60 Hz on NTSC), a different number of players… not to mention games that only ever existed in a single region.
The brackets and parentheses appended to rom names encode the region, the revision and the state of the dump. To decode them, see Tags used in rom filenames.