OptiFine HD 9minecraft — FAQ

Troubleshooting

Installer won't open: ensure Java is installed and associated with .jar files.
Profile missing in the launcher: re-run the installer and pick the correct folder, then restart the launcher.
Shaders look wrong or crash: try a different or lighter shader pack; some packs need specific settings.
A mod conflicts: remove recently added mods one at a time to find the culprit.

Is it free? Yes. Grab a free key from the download page.

Do I need other mods? No – everything you need is bundled in the single installer.

Does it work with resource packs? Yes, including packs that use connected textures and custom entity models.

Can I use shaders and still get good FPS? Yes – the rendering engine is built for speed; pick a shader pack that matches your hardware.