You ran the installer, but it can’t locate your Minecraft installation (common with third-party launchers like CurseForge, ATLauncher, or Prism). The Fix: Run the .jar file again. Click the three dots next to the folder path ( ... ) and manually navigate to your Minecraft game directory (e.g., %appdata%\.minecraft or the instance folder of your launcher).
In 99% of cases, what you are seeing is a file naming issue caused by your operating system or browser. Here’s why: optifine zip file