Minecraft crash codes and messages

The launcher reads the log after a crash itself and writes the cause in the “Game crashed” window. Below are common codes and messages, what they mean, and which button fixes them. For the general procedure, see the article The game crashes or shows a black screen — what to do.

Exit code 1

Code 1 only means “the game exited with an error” — the cause is in the log. The launcher shows it on the first line: “The game failed to start (code 1): …”. Look for your case below in the text after the colon.

If there is no text — open the modpack → the “Logs” tab and look at the last lines with ERROR or Exception.

-1073741819 (0xC0000005)

Memory access violation. The launcher shows this code as 0xC0000005. It is almost always a crash inside the graphics card driver, and less often antivirus interference.

1. Update your graphics card driver from the NVIDIA, AMD or Intel website. If the launcher recognized the driver, the crash window will have a “Download driver” button.
2. On a laptop, switch the graphics card: modpack → “Settings” → “Graphics card”.
3. Add the launcher folder to your antivirus exclusions.

-1073740791 (0xC0000409)

Abnormal process termination. The launcher shows it as 0xC0000409. Most often this is also a graphics card driver — follow the same steps as in the previous section.

0xC0000135 and 0xC000007B

A system library was not found. Install Microsoft Visual C++ Redistributable from the Microsoft website (x64) and restart your computer.

“Pixel format not accelerated”, “Failed to create window”, OpenGL

The game could not open a window: the graphics card or driver does not provide the required OpenGL. The crash window will say “The game could not open a window — it is the graphics card or its driver”.

1. Update your graphics card driver. The driver Windows installed by itself often has no OpenGL — you need the driver from the manufacturer's website.
2. On a laptop with two graphics cards, check the “Graphics card” line in the modpack settings. If the game crashes when opening a window on the discrete card, the launcher switches the modpack to the integrated one itself and offers to launch again.

Not enough memory

Messages: java.lang.OutOfMemoryError, Java heap space.

The crash window will say “Not enough RAM” and have an “Allocate … GB of memory” button — click it and launch the game again.

Another case is Could not reserve enough space, Insufficient memory for the Java Runtime Environment, paging file is too small. Then the computer itself did not have enough memory. Giving the game more memory will make things worse: set less, close your browser and heavy programs, and check that the Windows paging file is enabled. For more details, see the article How to allocate more RAM.

Mixin apply failed

A message like Mixin apply failed … or MixinApplyError means a mod did not match this game version or a neighboring mod. The crash window will say “One of the mods did not match this game version (mixin error)”.

If the launcher identified which mod it is, the window will have “Update ‘…’” or “Disable ‘…’” buttons. Otherwise click “Repair modpack” — it removes mods that are not for the right game version. You can also ask Milli: the “Ask AI” button reads the log and names the guilty mod.

Missing dependency: a mod is missing

Messages: requires … which is missing, Missing or unsupported mandatory dependencies, MissingModsException.

The mod needs another mod or library (often Fabric API, Architectury, Cloth Config). The crash window will have an “Install ‘…’” or “Install dependencies” button — the launcher will find and install what is missing.

If the mod needs a different version of the dependency — the “Change version of ‘…’” button. If the mod needs a newer loader — “Update loader”.

A mod is not for this version or not for this loader

• “The mod was built for a different game version” — click “Disable ‘…’” or install the mod version for your game version.
• “The mods folder contains a mod for a different loader” — for example, a Forge mod in a Fabric modpack. Remove it or install the version for the modpack's loader. For more on loaders, see the article Fabric, Forge, NeoForge and Quilt.
• “Mod conflict — there are duplicates or incompatible mods” — two files of the same mod or mods that do not work together. Remove the extra one.

The game closed without a line in the log

Most often the game was closed by antivirus. Add the game folder to exclusions: the “Open modpack folder” button in the crash window will show you which folder to add.

Nothing worked

Click “Share log” in the crash window and send the link to support — Telegram @MillidaTeamBot. If it is your server crashing rather than the game, see The server crashed: what to do.