Winols 451 Vmware Fix May 2026

Running WinOLS inside Windows 10/11 Sandbox (which is Hyper-V based) is rarely successful. Microsoft Hyper-V leaves many artifacts that WinOLS detects easily. Avoid this route.

The software uses several low-level detection techniques:

When any of these tests return a positive result, WinOLS halts execution and throws the 451 error.

Step 1: Shut down the virtual machine completely.
Do not just suspend; perform a full shutdown from the guest OS. winols 451 vmware fix

Step 2: Locate the .vmx file.
Go to the folder where your VM is stored (e.g., Documents\Virtual Machines\WinOLS_VM). Find the file named YourVMName.vmx.

Step 3: Make a backup.
Copy the .vmx file to YourVMName.vmx.backup before making changes.

Step 4: Open the .vmx file in a text editor (Notepad, Notepad++, or VS Code). Running WinOLS inside Windows 10/11 Sandbox (which is

Step 5: Add the following lines at the end of the file. These parameters are known to defeat the most common anti-VM checks in WinOLS 451:

# Disable VMware backdoor I/O port
isolation.tools.setVersion.disable = "TRUE"
isolation.tools.getVersion.disable = "TRUE"
monitor_control.restrict_backdoor = "TRUE"


Some advanced users use USBPcap or USB Network Gate to forward a physical dongle from the host to the VM. This often bypasses WinOLS’s VM checks because the dongle is physically present on the host.

For users who are not comfortable editing .vmx files manually, there are community tools that automate the process. When any of these tests return a positive
SMBIOS.noOEMStrings = "TRUE"
mce.enable = "TRUE"
The nuclear option: Dual-boot Windows 10 on bare metal. No VM, no error. Use WinOLS natively without any fix.

Even after the fix, you may encounter issues. Here is a diagnostic table.
| Problem | Likely Cause | Solution |
| :--- | :--- | :--- |
| Still getting Error 451 | The VMX lines were ignored or typed incorrectly. | Double-check the .vmx syntax. Remove spaces around =. Ensure VM is powered off completely (not suspended). |
| WinOLS crashes on launch | Bad patch applied; memory corruption. | Reinstall WinOLS 451 clean. Use only the VMX fix, not a binary patch. |
| VM runs extremely slow | Too many monitor_control lines. | Remove monitor_control.disable_directexec = "TRUE". Keep only monitor_control.restrict_backdoor = "TRUE". |
| USB dongle not detected | VMware USB arbitration service not running. | On host PC, start VMware USB Arbitration Service (services.msc). Set to Automatic. |
| Network disappears | VMX fix caused NIC reset. | Re-add the virtual network adapter via VM Settings. |