Pre-requirements

Before installing OptiFine, you may need to install some things first to ensure the installer runs properly.

Java runtime

You may need to install a Java runtime (JRE) above version 8. It is not recommended to use Oracle's Java. Instead, use Adoptium's (formerly AdoptOpenJDK) Java runtime.

You can choose to install any JRE; all work with the OptiFine installer.

  1. Go to https://adoptium.net/temurin/releases/

  2. Under the Operating System filter box, select Windows.

  3. Under the Package Type filter box, select JRE. You do not need the JDK.

  4. Under the Architecture filter box, select x64.

  5. Under the Version filter box, select any number; they are all >= 8.

  6. Click the blue button labeled .msi.

  7. Execute the downloaded MSI file.

  1. Go to https://adoptium.net/temurin/releases/

  2. Under the Operating System filter box, select Linux.

  3. Under the Package Type filter box, select JRE.

  4. Under the Architecture filter box, select x64.

  5. Under the Version filter box, select any number; they are all >= 8.

  6. Click the blue button labeled .tar.gz.

  7. Extract the files inside the archive into your PATH; you may need to use sudo for this.

  1. Go to https://adoptium.net/temurin/releases/

  2. Under the Operating System filter box, select macOS.

  3. Under the Package Type filter box, select JRE.

  4. Under the Architecture filter box, select x64.

  5. Under the Version filter box, select any number; they are all >= 8.

  6. Click the blue button labeled .pkg.

  7. Execute the downloaded PKG file.

Jarfix

_images/jarfix.webp
_images/jarfox.webp

A jarfox

If you have the Java runtime installed, but can't open .jar files with it, you may need to install Jarfix. Jarfix is an application that fixes the file association on Windows, so that JAR files will be executed as Java programs.

Download it from https://johann.loefflmann.net/en/software/jarfix/index.html and run it.

Important

This is only for Windows. This issue does not occur in Linux or Mac.

Assumes latest OptiFine version.
Updated to commit 8ed2130d.
Open source at https://gitlab.com/whoatemybutter/optifinedocs.