Facepunch shipped the September 2026 Update for Garry’s Mod on 16 September 2026, and its highlight section leads with the item server operators have asked for longest: 64-bit binaries on Windows. The post, credited to project lead Rubat, lists 64-bit builds for “the Windows game client, dedicated servers and most developer tools, such as Hammer”, and states the benefit in the game’s own terms — less risk of running out of the 32-bit memory address space and crashing while playing on heavy servers or with a lot of addons installed.
That sentence is the update’s centre of gravity. Garry’s Mod’s best-known failure mode on addon-heavy servers was never a shortage of memory in the machine; it was a shortage of address space in the process, and those are different problems that produce the same symptom.
What changed: the Garry’s Mod September 2026 Update (16 September 2026) adds 64-bit Windows builds of the client, the dedicated server and most developer tools, alongside Sandbox content changes, a new mountable game, dedicated-server housekeeping convars and a long list of engine and Lua fixes. Why it matters: a 32-bit process cannot use more memory than its address space allows, so large Workshop collections and heavily scripted servers crashed no matter how much RAM the machine had. The 64-bit client is selected from Steam launch options. Who should care: server owners running big addon collections, Sandbox and TTT players, and map or model authors who work through Hammer and StudioMDL.
The update at a glance
| Area | What shipped | Practical effect |
|---|---|---|
| Windows client | A 64-bit build, selectable from Steam launch options | Addon-heavy sessions stop hitting the 32-bit address-space ceiling |
| Dedicated servers | A 64-bit build, plus srcds_console.exe | Long-running servers gain address space and a console variant that reuses one window |
| Developer tools | 64-bit Hammer, Facepunch’s own builds of four tool binaries, a much larger StudioMDL buffer | Level and model work on large assets stops failing at the old limits |
| Content | Hacked Manhacks, a damageable Dropship NPC in Sandbox, spawnmenu sub-categories, a rebuilt player model selector | More built-in Sandbox content and faster menu navigation |
| Mounting | Standalone Insurgency (2014) added to the mountable games list | One more source of maps and models for players who own it |
What the 64-bit builds actually fix
A 32-bit process has a fixed address space no matter how much physical memory the machine holds, so a large Workshop collection or a big map can exhaust it and bring the engine down while the system itself is nowhere near out of memory. Capacity and address space are separate purchases; our CAMM2 guide covers the capacity side, and this update is the other half.
Facepunch’s wording stays measured on the outcome: the update means “less risk” of the crash, not the elimination of it. Two smaller facts around the change matter for anyone planning a build.
First, 32-bit has not been withdrawn. The blog post says the 64-bit game client “can be selected from Steam launch options”, and the 17 September hotfix separately fixes a start-up crash on “native 32-bit Linux client” — so the older client remains part of the shipped game. Second, Facepunch’s public commit log records a follow-up change titled “Force 64bit builds as the default”, describing gmod.exe relaunching with gmod_win64.exe on 64-bit systems “exactly like TF2 does”, with -force32bit kept for anyone who wants the older client. That commit is not in the September changelist, and the log shows it at a date relative to the reader rather than an absolute one, so treat the default as a moving target: the September update made 64-bit available, and a later change made it the path of least resistance.
The scope is also worth reading exactly. The post names the Windows client, dedicated servers and “most developer tools” — the binaries that grew on Windows are the ones named, and the changelist entry reads “64-bit builds of the game client, Hammer and dedicated server are now available on Windows”. The pre-release announcement had advertised an x86-64 beta branch alongside prerelease and dev as the testing grounds for the change.
What changes for server owners
Beyond the binaries, the changelist carries an unusual amount of housekeeping aimed at boxes that stay up for months. All of the following wordings are the developers’ own.
| Change | Detail from the changelist | What it is for |
|---|---|---|
srcds_console.exe (Windows only) | An srcds.exe variation “that does not create a new console window every time and reuses existing one” | Servers behind a wrapper or panel that already owns a console |
sv_log_storetime | New convar, default 0 — “A number of hours to keep log files in /logs/ for” | Log rotation without an external script |
sv_logdownloadlist | Now defaults to 0, “preventing generation of useless files in garrysmod/DownloadLists/” | Stops a directory nothing reads from filling up |
cache/workshop/ | Cleaned on dedicated servers of Workshop content for addons “no longer used/installed” | Reclaims space that accumulated over years |
sv_pure | “Prevented sv_pure defaulting to mode 0”, and servers no longer “try to read files we don’t ship every server startup” | Removes recurring start-up noise |
| Log filenames | New format L-YYYY-MM-DD-III, replacing LMMDDIII — “incomprehensible at a glance” | Logs that sort and read by date |
| Lua error logs | Files over 100 MB are now deleted | Bounds a directory that could grow without limit |
| Nav files | sv_no_ain_files removed; the game “just do[es] not auto send .nav and .ain files to clients at all” | Less traffic on join |
The scheduling question was answered before release. In the 9 September announcement, Facepunch set the update for “16th of September at 3PM GMT” and said it “will be backwards compatible with existing servers, so servers will not need immediate updating and players can still join old servers” — while recommending updating anyway “to get all the new features and fixes”. That is a compatibility statement about connecting, and this site has no basis to extend it into a promise that every addon behaves identically; test a copy before rolling a heavily scripted server forward.
For scale, SteamCharts’ public tracker records Garry’s Mod’s September 2026 peak at 38,412 concurrent players with a monthly average of 21,234.53 — third-party estimates from Valve’s public numbers, but a reasonable picture of how many addon-heavy sessions this change touches.
Sandbox and content changes
The headline content addition is small and specific: NPC variation Hacked Manhacks was added to the spawnmenu. More consequential for Sandbox players is the Dropship NPC, which the changelist says is “no longer invincible in Sandbox” — it can take damage when spawned, and a related fix stops it “being able to remove players”.
The menu work is where most players will feel the update. Content tabs in the spawnmenu gained sub-categories, and Facepunch notes the system “is open for addons to take advantage of”, so custom content can organise itself the same way. Search now supports multiple terms and also returns results for localized names. The player model selector was rebuilt: bigger, grouped into categories, with player-friendly names and rendering that “better represents how the player model would actually appear in the game world”. The Addons menu gained a “Downloaded” category.
Insurgency (2014), the standalone release, joined the mountable games list, following the April 2026 additions of Black Mesa and Military Conflict: Vietnam. Mounting works as it always has: you need to own the game on Steam, and doing so exposes its maps and models to Sandbox and other gamemodes.
Two smaller combat-facing changes are worth knowing before a match. The AR2’s default clip was reduced “to match its clip size, and to be consistent with SMG1 and original Half-Life 2 behavior. This affects how much ammo you get when picking up the weapon from ground. (from 60 to 30)”. And Combine APC vehicles “can now explode without a driver”, with the exploded vehicle replaced by the big gib model in the undo and cleanup systems.
Modder and developer tooling
Hammer, the level editor, ships in 64-bit form for the first time here, and got a pass of its own: improved DPI scaling, wider Map Errors and Entity Report dialogs, a prompt for a name when the entity picker hits an unnamed entity, and a fix for the Carve command wiping overlays that were not carved. Facepunch also started shipping its own builds of vtf2tga, splitskybox, captioncompiler and elementviewer, which the changelist describes as “previously were pre-built 2013 versions”, and removed glview.exe, height2normal.exe and height2ssbump.exe as “unused or useless”.
The compile tools moved too. StudioMDL’s file buffer limit went “from 32MB to 128MB so large models can be written without crashing”, VBSP gained -embed support, and BSPZIP gained compression via a -repack argument “ported from Team Fortress 2 version”. Hammer also added a Toggle input to func_nav_avoid and func_nav_prefer, new model-entity inputs (SetModel, SetCycle, SetPlaybackRate) imported from Team Fortress 2, and “Portal Visualization Width” among its 3D settings.
The Lua API additions are wide but shallow — mostly small conveniences for addon authors:
| New API | What it does |
|---|---|
physenv.SetTimeScale, physenv.GetTimeScale | Read and write the physics time scale |
player_manager.GetAllPlayerModels | Returns every valid player model with categories and nice names, alongside new AddValidModel arguments and a RemoveValidModel |
util.IsPlayerSpeaking | Query whether a player is currently talking |
timer.IsPaused | Check a timer’s state |
Entity:EmitStepSound | Trigger a step sound from Lua |
math.Sign | Sign of a number, a community contribution |
render.Capture formats | Three additions — rgba, rgb and bgra |
Underneath, the technical changelist updates the Steamworks API “to version 1.64”, turns host_state.interval_per_tick “into double”, switches Lua timers “to use double precision curtime”, and implements “partial prediction latch resets from Team Fortress 2 SDK” so that weapon prediction errors no longer reset every predictable variable and jolt the player’s position. If that vocabulary is unfamiliar, the netcode glossary on this site defines tickrate, jitter, prediction and interpolation as patch notes use them. Legacy Windows instruction sets were dropped: “Disabled MMX and 3DNow code - it was never really used by modern computers and was only implemented for 32bit Windows”. A large share of the list carries the tag “(Community Contribution)”.
The 17 September hotfix and two open issues
The update was followed a day later by a hotfix, announced inside the same Steam post. It re-enabled the ability to override suit and health charger entities and Combine mines with Lua entities, added solution steps to the “Failed to init Steamworks” crash dialog, fixed addons with unusual filenames refusing “to be mounted on Linux dedicated servers”, added panel fallbacks to prevent Lua errors from community addons, and fixed the start-up crash on the native 32-bit Linux client by changing the image format of the _rt_ResolvedFullFrameDepth texture “to RGBA8888”.
Two known issues shipped alongside the fix list, and Facepunch is explicit about the first: sometimes deleting Workshop items from the new “Downloaded” category does not delete them, which the notes call “a bug with Steam, not Garry’s Mod”. The second is the one that generates misleading bug reports — the game “may not launch if your Steam client is outdated, or using Proton version below 11”, so the fix is to update Steam and use “latest version of Proton that supports the latest Steamworks SDK”.
Should you update, and what to check
The changelist is long and the risk profile is low, because the update was designed not to break the existing server population. Three practical notes:
- If you run a large Windows server or an addon-heavy Sandbox, this is your update. The 64-bit dedicated server and client are the entire reason the release exists for that audience, and the log and cache housekeeping convars are worth applying at the same time.
- If you run a small private server, nothing forces you. Facepunch’s own pre-release note says old servers remain joinable; updating is a recommendation, not a deadline.
- Test a copy if your server is heavily scripted. Compatibility as stated covers connecting, so treat addon behaviour as unverified until you have run it yourself.
One branch detail is worth checking on the server side before assuming you received the new binaries. The 9 September announcement lists three test branches — Pre-Release, dev and x86-64 — and a pinned branch does not necessarily move when the default one does.