How do I install an MLO in FiveM?

Put the MLO folder in resources, make sure its fxmanifest.lua includes this_is_a_map 'yes', add ensure foldername to server.cfg and restart the server.

Why is my MLO invisible?

The resource did not start, an escrowed MLO is not owned by your server’s Cfx account, or another map overlaps the same location.

What does this_is_a_map do?

It marks the resource as a map so its map data is loaded as such. MLO and map resources include it in their manifest.

Why do I fall through the floor of an MLO?

The collision file is missing, not streamed yet, or overridden by another map. Check the .ybn files are present and look for conflicting maps.

How to Install an MLO in FiveM (and Fix Missing Interiors)

MLOs are custom interiors — a police station you can walk into, a nightclub, a mechanic’s workshop — and they are what make a city feel lived in. Installing one is usually as simple as dropping a folder in and adding one line, but when two maps claim the same space or a file is missing, the symptoms (invisible walls, floating props, falling through the floor) are confusing. This guide covers both.

Short answer: An MLO is a resource whose stream folder holds the interior’s models (.ydr), textures (.ytd), collisions (.ybn), placement (.ymap) and archetype definitions (.ytyp). Its manifest usually needs only fx_version, game and this_is_a_map 'yes'. Add ensure for it, make sure no other map occupies the same place, and start map dependencies (such as bob74_ipl) in the order the MLO expects.

#What is inside an MLO

File type	What it is
`.ydr` / `.ydd`	Models (drawables and drawable dictionaries)
`.ytd`	Textures
`.ybn`	Collisions — what you can walk on and bump into
`.ymap`	Placement — where the interior and its props sit in the world
`.ytyp`	Archetypes — the interior’s definition, rooms and portals

“MLO” (Milo) is the game’s term for an interior with rooms and portals, which lets the engine hide what is outside when you are inside. That is why a proper MLO performs better than a building made of loose props.

#Installing

Unzip the MLO into resources/[maps]/ and check the folder contains fxmanifest.lua directly (not a folder inside a folder).
Open the manifest: it should look like the example below.
Add ensure the_mlo_name to server.cfg, after any dependency the author lists.
Restart the server and walk to the location.

fxmanifest.lua for a typical MLO

fx_version 'cerulean'
game 'gta5'

this_is_a_map 'yes'

-- files in stream/ are streamed automatically

Some MLOs also register their .ytyp explicitly with data_file 'DLC_ITYP_REQUEST' 'stream/name.ytyp'. Keep whatever the author shipped; do not add it if it is not there.

#Escrow (FXAP) MLOs

Most paid MLOs are protected with Cfx asset escrow. The files are encrypted and only decrypt on a server whose license key belongs to the Cfx account that bought the asset. If an escrowed MLO shows nothing, check that the server uses the right license key and that the asset is assigned to that account in the Cfx portal. Escrowed files cannot be opened or edited, so a broken escrowed MLO has to be fixed by its author.

#Conflicts: the source of most MLO problems

Symptom	Likely cause
Invisible walls or walking into air	Collision from another map at the same spot
Interior flickers or props pop in and out	Two maps overlap and both draw there
Interior is empty or missing	The ytyp did not load, the MLO did not start, or an IPL loader removed it
Falling through the floor	Collision (`.ybn`) missing or not streamed yet
Original building still visible inside	The MLO expects a vanilla object to be removed; a required dependency is missing

Many MLOs replace or build on vanilla interiors that bob74_ipl also manages. If both edit the same interior, start the MLO after bob74_ipl, or disable that interior in bob74_ipl’s config. Interiors and IPLs explains how IPL loading works.

#Performance and memory

Every MLO adds textures and models that clients stream when near it. A detailed MLO can easily carry textures above the size FiveM warns about; the server prints an “Asset … uses X MiB” line for anything over 16 MiB. Dozens of heavy MLOs downtown are a common cause of textures loading slowly or not at all — see the oversized assets warning.

Installing MLO interiors on a FiveM server