Memory Leak Fix | Stop RAM Creep in Long Play Sessions

If your client or server feels quick at launch, then drags the longer it runs, you are probably paying for a memory leak, and Memory Leak Fix goes straight after that problem. It patches several holes in Minecraft's own code where the game grabs memory and never gives it back, and it works on both the client side and the server side. That focus earned the mod roughly 39 million downloads from players tired of restarting just to free up RAM. One honest caveat up front, the developer states that later versions of Minecraft fixed the leaks this mod targets, so the project is officially obsolete going forward. On older game versions, where those cleanups never happened, the version table on this page shows at a glance if the mod still applies.

The Leaks Behind Your Creeping RAM Usage

The developer's final release bundles seven leak fixes, and the headline targets biome temperature data. Vanilla kept a broken cache for biome temperature operations, and the mod makes that cache work the way it should. The project wiki reports a significant performance boost for large biome temperature operations while using a lot less memory, which matters most for players who generate terrain constantly or run worlds stuffed with custom biomes.

The rest of the list reads like small holes that drain a bucket drop by drop. Dead mobs never cleared out their brain data, so the memories of every corpse you left behind piled up in memory, a big cost on busy mob farms (MC-260605). A tag cache never emptied, so setups loaded with custom recipes, tags, and loot tables leaked a little more on every load (MC-248621). Drowned kept their very first navigation object forever (MC-202246). On the client side, returning to the main menu without fully closing the game left the crosshair target behind, and that one leftover object kept the entire world loaded in memory until you killed the process (MC-101260). Two more cover a texture buffer that leaked when an exception hit and an oversized in-game image allocation that was never released.

Mojang has since fixed most of these in its own updates. On the newest game release the mod supports, only a couple of the seven still change anything, which is why the project wound down.

Client and Server, Run It on Either Side

This mod treats client and server as separate jobs, and it is optional on each side. Run it on your client and long play sessions stop slowly eating system memory. Run it on a dedicated server and the RAM creep that builds up over days of uptime stays under control. Running both covers everything.

The official project page also recommends pairing it with a general performance mod like Lithium and a memory-focused option like FerriteCore. We have covered that space from other angles too, ModernFix trims RAM through faster launches and leaner caching, while Krypton cuts the network overhead that makes server ticks crawl.

No Config File, Nothing to Tune

Memory Leak Fix is close to install-and-forget. It checks your game version at startup and turns on only the fixes that still apply, then logs a line like "[MemoryLeakFix] Will be applying 3 memory leak fixes!" along with the list of active fixes. There is no documented config file and no individual toggles, so if that log line shows up, you are done. The log doubles as the quickest way to count how many fixes are live on your setup. Pack builders get a nod in the license too, the author allows the mod in modpacks as long as you credit it, while merging it into a client or another mod needs permission first.

How to Install Memory Leak Fix

1. If you have never installed a mod before, read our guide on how to install Minecraft mods first so the folder locations make sense.
2. Memory Leak Fix ships in Fabric, Forge, and Quilt editions, so make sure the loader that matches your setup is installed. If Fabric is your pick, our Fabric loader guide walks through it.
3. Download the file for your loader from the official project page, and skip the random reupload sites entirely.
4. Drop the jar into your mods folder. For a server, place the same file in the server's mods folder.
5. Start the game or restart the server, then check the log for the MemoryLeakFix startup line to confirm it loaded.

Memory Leak Fix FAQ

Does Memory Leak Fix work on both the client and the server? Yes. It fixes leaks on both sides and is optional on each one, so you can run it on your client only, on your server only, or on both for full coverage.

Does MemoryLeakFix have a config file? No. The mod decides which fixes still apply to your game version, applies them automatically, and lists them in the startup log. There are no individual toggles.

Does Memory Leak Fix improve FPS? Not directly. It targets memory usage rather than rendering. The payoff shows up as less RAM waste during long sessions, plus a significant performance boost in large biome temperature operations, the area its strongest fix handles.

Is Memory Leak Fix still being updated? The last release shipped in January 2024. The developer states that later versions of Minecraft fixed the leaks the mod targeted, which made the project obsolete going forward, and the GitHub repository has since been archived and set to read-only. A community follow-up called AllTheLeaks carries the idea onto newer releases.

Once your RAM stops climbing, the small wins in our BadOptimizations post are the next step. Longer sessions, fewer restarts, no babysitting.