If you are seeing error code , a “License not found” message, or a crash on startup inside VMware Workstation or VMware ESXi, you have encountered the classic WinOLS 451 anti-VM protection .
This article provides a to the WinOLS 451 VMware fix, including why the error happens, how VMware tools interfere, and several proven methods to bypass the restriction. Chapter 1: Understanding Error 451 in WinOLS What is Error 451? In the context of WinOLS, error 451 is not a standard Windows system error. It is a custom protection mechanism built into the software (or its accompanying driver/hardware key emulator) to detect if it is running inside a virtualized environment. winols 451 vmware fix
# Disable hypervisor CPUID leaf hypervisor.cpuid.v0 = "FALSE" cpuid.coresPerSocket = "1" Remove hypervisor bit from CPUID cpuid.1.ecx = "0:---:-:----:----:----:----:----:--0:----" cpuid.80000001.ecx = "0:----:----:----:----:----:----:----:----" Additional isolation flags monitor_control.disable_directexec = "TRUE" prefvmx.minVmMemPct = "100" If you are seeing error code , a
monitor_control.disable_directexec = "TRUE" can slow down your VM significantly. Use it only as a last resort. Chapter 5: Alternative Fix – Using VMware Unlocker Tools For users who are not comfortable editing .vmx files manually, there are community tools that automate the process. What is VMware Unlocker? Originally created to run macOS on VMware, some forks include scripts to “de-vmware” a virtual machine by patching the VMX binary and the guest’s registry. In the context of WinOLS, error 451 is
Copy the .vmx file to YourVMName.vmx.backup before making changes.
# Disable VMware backdoor I/O port isolation.tools.setVersion.disable = "TRUE" isolation.tools.getVersion.disable = "TRUE" monitor_control.restrict_backdoor = "TRUE" smbios.reflectHost = "TRUE" hw.model = "MacBookPro11,3" bios.vendor = "American Megatrends Inc." bios.version = "5.11" Disable VMware-specific CPUID cpuid.1.ecx = "0:----:---:---:----:----:----:----:----" cpuid.1.edx = "---:----:---:----:----:----:----:----:----" Hide VMware from DMI/SMBIOS tables SMBIOS.noOEMStrings = "TRUE" mce.enable = "TRUE" Fake disk and network vendor strings disk.enableUUID = "FALSE" ethernet0.virtualDev = "e1000e"
Introduction WinOLS is the gold standard in the automotive tuning industry. It is the go-to software for ECU (Engine Control Unit) mapping, allowing tuners to modify fuel maps, ignition timing, torque limiters, and more. However, version 451—specifically the variant often distributed with dongle emulators or patched license files—has a notorious reputation for refusing to run inside a virtual machine (VM).