If it's a FitGirl repack, check the box that says before starting the extraction. Technical Workarounds
This is the most common cause. Decompression tools like lolz behave similarly to malware (they unpack encrypted data rapidly), causing Windows Defender or other antivirus software to silently block or quarantine the file. failed to start cls-lolz x64.exe
Critical launch failure – cls-lolz x64.exe cannot start. Affected software: Unknown (likely a game modding tool, cheat engine, system utility, or legacy software package). User sentiment: Extremely negative due to lack of clear error resolution. If it's a FitGirl repack, check the box
Permissions and file locks
Right-click the setup.exe and select Run as Administrator to ensure the installer has the permissions to launch sub-processes. If it's a FitGirl repack