A: Proceed with caution. It can break system stability. Use only on a test partition.
Introduction: Why Windows 7 Users Still Need OptiFine opticraft minecraft windows 7 fix
If you absolutely must play the latest Minecraft with shaders on Windows 7, consider upgrading your OS to Windows 10 LTSC (lightweight) or Linux (Ubuntu or Mint), where OptiFine runs natively with no hacks. A: Proceed with caution