Track 1 / New users

Play Minecraft with CT, step by step.

This guide uses plain language only. No jargon, no source code, and no prior knowledge assumed. Follow the sections in order and you will be playing.

Step 1

What you need

Three things. Check them once and you are ready.

1A computerWindows, macOS, or Linux. Any modern machine is fine.
2Java (JDK 21 or newer)This is a free program that runs CT. If you do not have it yet, install JDK 21 or a newer version from any trusted provider.
3InternetNeeded to download the game files. The first download is the big one, so a normal connection is enough.

The Java that runs Minecraft itself is downloaded automatically by CT. You only install the JDK for CT.

Step 2

Install CT

CT-Main is the main file. The features are small module jars that install themselves into it. Three small actions.

1Download everything (easiest)Get CT-Client-4.3.0-full.zip from the Downloads page, unzip it, and double-click Start CT-Main.command (macOS) or Start CT-Main.bat (Windows). All modules are already inside — you can skip step 2. Prefer to pick modules yourself? Get CT-Main-4.3.0.jar instead and start it once so it creates its modules folder.
2Drag the modules onto the installerOn the module page, download the module jars you want, then drop them all onto Install modules.command (macOS), Install modules.bat (Windows), or CT-Main-4.3.0.jar. CT-Main installs each one into its modules folder, fetches any module they require, and opens with them loaded. One at a time also works: double-click a module jar. Stuck? The install guide has the fixes.
3Start itRun the command below. The first start shows WELCOME TO MINECRAFT-CT; with the modules installed it shows the full launcher.

java -jar CT-Main-4.3.0.jar

Without any modules you still see the welcome window — that is normal. The window fills up as you add modules. Prefer building it yourself? Run ./mvnw package in the project source; the build produces CT-Main and every runnable module jar, or follow build a module to write your own.

Step 3

Launch the game

One window, two fields, one button.

1Pick a versionUse the version box to choose the Minecraft version you want. Any version in Mojang's official list is there.
2Press LaunchThat is all. If the game is not installed yet, CT installs it first, automatically.

The very first launch takes a while, because CT downloads the game, its libraries, and all its files, and checks each one. Watch the progress bar and the console in the launcher window. Later launches are fast because everything is already on disk.

Step 4

Choose an account

There are two ways to play. Pick the one that matches what you want to do.

ONLINE PLAY

Microsoft account

Use this to play on online servers with the account you bought the game with. Press sign in in the launcher. A short code appears on screen. Open the website it shows you, type the code there, and sign in with your Microsoft email and password. That is the whole flow — no setup and no client ID needed.

Prefer your own Azure application? Switch the sign-in method in settings and set your client ID there.

TESTING

Offline profile

Use this for single-player testing. One click, and a local profile is ready. No sign-in, no client ID, no waiting.

An offline profile cannot join online-mode servers. It is for trying things out, not for real online play.

Access tokens are never saved to disk. A Microsoft sign-in lasts for the current launcher session, and the offline profile is selected again with one click.

Step 5

Add mods in three steps

Mods are just files you place in one folder.

1Open the mods folderIt lives inside the game directory. Per-platform instructions, including how to reach the hidden folder, are on the mods page.
2Drop the files inCopy each trusted .jar file straight into that folder. No installer needed.
3Restart the gameClose the game, then launch again from CT. The mods load on startup.

Mods are executable code. Only use JAR files you trust, from sources you trust.

Step 6

Change RAM and window size

Two settings people ask about most: how much memory the game gets, and how big the window is.

RAM is the working memory the game may use. More RAM helps with heavy mod packs. The minimum is the smallest amount the game always gets, and the maximum is the most it may take.

Window size controls how many pixels wide and tall the game window opens. You can also leave it off and let the game decide.

Important: edit these in the settings file, not in the launcher window. The window fields for memory and resolution are read from ~/.ct-client/settings.properties when the window opens, and the launch reads the file again, so changing them in the window does not change the next launch. See why the window fields behave this way.

Open the file ~/.ct-client/settings.properties in any text editor and set the lines you need:

memory.minimumMb=2048
memory.maximumMb=4096
resolution.custom=true
resolution.width=854
resolution.height=480

Save the file and launch again. Numbers must be sensible: the maximum cannot be smaller than the minimum, and the resolution cannot be smaller than 320 by 240.

Step 7

Five common problems, five easy fixes

If something goes wrong, it is almost always one of these.

Problem	Fix
The game does not start at all	Install Java 21 or newer, then try again. CT needs it to run.
The message `Enter an Azure application client ID` appears	The custom method is selected but no client ID is set. Follow setting the client ID, or switch back to the built-in sign-in.
Microsoft sign-in fails	The account must own Minecraft Java Edition. If it does not, sign-in cannot complete. Use an offline profile for testing instead.
A download is interrupted	Press install again. Verified files are kept, so the install resumes instead of restarting.
Mods do not load	Each mod JAR must be directly inside the `mods` folder of the game directory, then restart the game.

Still stuck? The troubleshooting page lists every known error with its cause and exact fix.