Garry's Mod September 2026 Update — 64-Bit Windows Builds, Sandbox Improvements & A Huge Fix List

Facepunch shipped the Garry's Mod September 2026 Update, and the headline is one server owners have been asking for since 2006: 64-bit binaries on Windows. The update brings 64-bit builds of the game client, the dedicated server and most developer tools including Hammer, alongside new Sandbox content, a reworked Spawnmenu and Player Model Selector, and an enormous list of smaller fixes and optimizations.

It's a devblog from Garry's Mod project lead Rubat, and it landed with three changelists — Game Changes and Developer Tool Changes, both dated 16 September 2026, plus a September 2026 Hotfix the following day.

The full change list comes straight from Facepunch — check out the entire Garry's Mod September 2026 changelog from the developers — and it's worth reading in full, because the "smaller stuff" section alone is dozens of entries long.

🖥️ 64-Bit Windows Builds — The Big One For Servers

The headline change: 64-bit binaries for the Windows game client, dedicated servers and most developer tools such as Hammer are now available to every version of the game.

Why it matters:

• Less risk of running out of the 32-bit memory address space. That address-space ceiling was the classic cause of crashes on heavy servers or with a lot of addons installed — the exact scenario most DarkRP, TTT and heavily-modded Sandbox servers live in.
• The 64-bit game client can be selected from Steam launch options, so players can opt in without waiting for anything else.
• Developer tools go 64-bit too, which means Hammer and friends stop being the weakest link when working on large maps and packs.

Facepunch also began shipping srcds_console.exe on Windows — an srcds.exe variation that doesn't spawn a new console window every time and instead reuses the existing one. Small quality-of-life win if you're restarting servers often.

🧱 New Sandbox Content

• Hacked Manhacks — a new NPC variation added to the spawnmenu.
• The Combine Dropship is no longer invulnerable in Sandbox and can now take damage when spawned.
• A new mountable game: standalone Insurgency (2014) was added to the mountable games list.

🔍 Spawnmenu, Menus & UI

• Spawnmenu content tabs now support sub categories for entities, NPCs, weapons and more — and the system is open for addons to take advantage of, which is good news for large content packs that previously dumped hundreds of items into one flat list.
• Sub categories were added to the Half-Life 2 ammo and consumable entities in the spawn menu.
• Spawnmenu search now supports multiple search terms (a community contribution).
• You can now hide disabled Sandbox tools (also a community contribution).
• A "Downloaded" category was added to the Addons menu, and the loading screen now shows more detail while downloading Workshop content.
• The default Player Model Selector was overhauled — bigger, with player model categories, player-friendly names, and improved rendering that better represents how the model actually looks in-game.
• Right-click menus with "reset to default color" and "copy to clipboard" were added to Color Selection, Key Binder and Slider UI elements — practical small stuff for the Player Model Editor and Sandbox tools.
• Spawn Icon Editor improvements — light presets, bigger size, more accurate previews.
• CTRL+Backspace and CTRL+Delete now work in text entries, and hitting a Sandbox limit repeatedly (like when spawning a dupe) now shows a single "you have hit the X limit" notification instead of spamming you.
• Dupes, saves and demos can be added to favourites from the main menu, with an indication of whether an item has been upvoted.

🎮 Gameplay, Engine & Exploit Fixes

• Two ladder exploits closed. A hull trace is now used for the "can we reach ladder" line-of-sight check — fixing the ability to attach to a Half-Life 2 ladder through certain walls with tiny gaps — and ladder dismount entities now use a line-of-sight trace, so players can no longer dismount through walls.
• Barnacles no longer tug forever at props frozen with the Physics Gun, and heavy or frozen props now make the Barnacle's tongue float above them rather than pass through.
• Prediction errors fixed for several built-in weapons — the Half-Life: Source .357 Revolver, Hornet Gun, Crossbow, Half-Life 2 Crossbow and SLAM.
• The AR2's default clip was reduced from 60 to 30, matching its actual clip size and original Half-Life 2 behaviour. This changes how much ammo you receive when picking the weapon up from the ground.
• Combine mines now ignore dead players, and the Combine APC can now explode without a driver (and gets replaced by the big gib model in the undo/cleanup systems when it does).
• NPCs now ignore spectating players who are alive — a subtle but real fix for spectator-influenced NPC behaviour.
• Citizens with an RPG equipped now hate gunships, dropships and helicopters, and will actually shoot at them.
• Fixed crossbow bolts, RPG rockets and SMG1 grenades hitting the surrounding bounds of weapons and ammo, and hitting invulnerable props with a crossbow bolt now applies physics force to them.
• The Inflator effect was updated so you can see what you're doing, and it now looks different between inflating and deflating.
• Convar cleanup: engine_no_focus_sleep was removed and replaced by fps_max_menu and fps_max_nofocus — far easier to understand than tuning "sleep time".
• Plus a long tail of fixes: ragdoll gib fade time and cleanup in multiplayer, SpawnIcon positioning, SuperDOF tiling and rendering, npc_turret_floor dying multiple times, the fixed-reticle convar restored, and Workshop download handling (cancelling active downloads on disconnect, and waiting for Workshop mounts when loading a map).

🧩 For Addon & Lua Developers

This update touches the Lua API in ways addon authors should read carefully.

• Removed: Lua can no longer modify various convars that save between sessions. If your addon writes persistent convars, check it — this is the most likely breaking change in the update.
• The built-in "VehicleMemDupe" entity modifier was removed (Facepunch's note: it "appears to really just do nothing useful").
• Hooks got more consistent: GM:PlayerStartVoice and GM:PlayerEndVoice are now called consistently even if the player entity doesn't exist, and both consistently receive the PlayerIndex argument.
• Hook ordering fixes: the order of GM:DrawOverlay, GM:PostRenderVGUI and GM:PostRender was changed so they cannot cover up the main menu, GM:PreRender's return value was disabled while the main menu is open, and Lua VGUI panels no longer overlap the main menu.
• Panel fixes: DHorizontalDivider now works with percentages instead of raw pixels (helpful for resizing and resolution changes), DColorMixer's palette is centred and sized properly, DColorMixer:GetVector is no longer one change behind, DLabel:SetDisabled stopped invalidating layout needlessly, and DPanelList/DPanelSelect behaviour was corrected.
• Bug fixes worth noting: Player:UnSpectate now fully cleans up (and Player:Spectate stopped sending three useless usermessages), cookie.GetString returns consistent types, Entity:Remove no longer removes prematurely with "crazy physics", string.FormattedTime's millisecond value was fixed, potential Lua stack corruption in GM:CreateClientsideRagdoll and GM:EntityEmitSound was addressed, and Entity:GetHitboxSetCount now returns a number for entities without a model.
• New additions: ToColor and Entity:BeingLookedAtByLocalPlayer, plus Lua matproxies can now exist without a bind function.

🛠️ Mapper & Developer Tool Changes

• Hammer: a new "Portal Visualization Width" option, improved UI DPI scaling, a name prompt when picking unnamed entities, wider Map Errors and Entity Report dialogs, sprite helpers inheriting entity colour, and fixes for crashes with .mdl sprites and certain materials, the Carve command wiping overlay faces, undo breaking info_decal previews, dead "Make hollow" arrows, missing tooltips, and an infinite loop with TokenReader::IgnoreTill that could lock Hammer on startup with a malformed custom .fgd.
• StudioMDL: the file buffer limit was raised from 32 MB to 128 MB, hardcoded DMX limits for normals/texcoords/faces were removed, support was added for noforceloop animations, $appendblankbodygroup, $preservetriangleorder and $bboxonlyverts, errors now display in red, and files with spaces in the path no longer break DMXConvert.
• Compiling: VBSP gained -embed support, BSPZIP got compression via a -repack argument ported from the TF2 version, and env_detail_controller was added to the FGD.
• Detail props fixed: detail props now appear on brushes using the WorldVertexTransition material when compiling, and Detail Objects render in Hammer at all.
• Facepunch now ships its own builds of vtf2tga, splitskybox, captioncompiler and elementviewer — previously pre-built 2013 binaries.
• Removed: the "Hinge Axis (Non functional)" field from prop_door_rotating and the useless "ReleaseVideoMemory" Hammer shell commands.

🔧 The Next-Day Hotfix

A September 2026 Hotfix followed on 17 September 2026:

• Re-enabled the ability to override suit/health chargers and Combine mines with Lua entities — worth noting if the main update interrupted an addon of yours.
• Fixed certain addons with weird file names refusing to be mounted on Linux dedicated servers.
• Added fallbacks in panel code to account for certain community addons and prevent Lua errors.
• Fixed a startup crash on the native 32-bit Linux client (the _rt_ResolvedFullFrameDepth image format changed to RGBA8888).
• Added solution steps to the "Failed to init Steamworks" crash dialog.

🖥️ What This Means For Your Server

• Move to the 64-bit dedicated server binary. This is the update the addon-heavy GMod community has wanted for years: the 32-bit address-space ceiling was the usual culprit behind crashes on packed DarkRP and TTT servers. More address space means more headroom for addons, dupes and big saves before something gives.
• Linux server owners: the hotfix matters. Addons with unusual filenames refusing to mount is the kind of bug that silently breaks a server's content — update to the hotfix build so your collection mounts properly.
• Audit addons against the convar change. Blocking Lua from writing session-saving convars is a deliberate hardening step, but it can break addons that relied on it. Test your collection after updating instead of discovering it on a full server.
• Players crash less, so reports drop. Between the 64-bit client and the memory-related fixes, the classic "server is broken, I keep crashing" wave should shrink — one of the more tiring things about running a big GMod community.
• Spawnmenu sub categories help your players. Custom content packs in your server's collection can now organise into sub categories, which makes a 500-item spawnmenu navigable instead of overwhelming.
• Update on a schedule, with a backup. GMod servers are frequent DDoS targets and update days are peak traffic — give yourself a world/config backup and mitigation you can rely on before you roll it out.

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Conclusion

The Garry's Mod September 2026 Update is the most consequential GMod update in years for server owners: 64-bit binaries for the client, dedicated server and dev tools finally remove the memory ceiling that has crashed addon-heavy servers for two decades. On top of that you get new Sandbox content (Hacked Manhacks, damageable Dropships, mountable Insurgency), a Spawnmenu with sub categories, an overhauled Player Model Selector, ladder and Barnacle exploit fixes, a serious Lua API cleanup including blocked persistent convars, a deep Hammer and StudioMDL pass, and a next-day hotfix that un-breaks Linux server addon mounting.

Want every last entry? Check out the entire Garry's Mod September 2026 changelog from the developers, and if you're planning an update night, see our Garry's Mod hosting plans.