: For specific builds like the Ultimate Edition, ensure virtualization (VT-x for Intel or AMD-V for AMD) is enabled in your BIOS.

: It is often necessary to temporarily disable Windows Defender or your antivirus during extraction and installation, as they may mistakenly quarantine the setup.exe or critical crack files. Step-by-Step Installation Guide Extract the Files

To install using the FitGirl Repacks multi-part RAR files, you must ensure that all parts (e.g., .part01 through .part15 and any subsequent files) are present in the same folder before beginning the extraction. Pre-Installation Requirements

: If your system has 8GB of RAM or less, check the box to "Limit installer to 2GB of RAM usage." This prevents crashes during the intensive decompression process.

: If installing on Steam Deck, use Proton GE and add the setup.exe as a non-Steam game to run the installer.

Select your installation directory. Avoid installing to "C:\Program Files" to prevent permission issues.

: Ensure you have downloaded every single part. If .part15.rar is the last part, verify that parts 1–14 are in the same directory.

: If VSync is forced on, navigate to %LOCALAPPDATA%\AtomicHeart\Saved\Config\WindowsNoEditor , open GameUserSettings.ini , and change bUseVSync from true to false .