Hypervisors are a game changer for IT reliability, scalability, and resource allocation. However, they can be tricky to manage and configure. Below we’ll detail many of the most common hypervisor errors, their fixes, and how you can prevent these errors moving forward.

How to Check Your Hypervisor Status

Verify Virtualization Support in BIOS/UEFI

Restart your computer and access the BIOS/UEFI setup by pressing the key prompted during startup (commonly F2, DEL, ESC, or F10). Navigate to the CPU or Advanced settings and ensure “Intel VT-x”, “AMD-V”, or “Virtualization Technology” is enabled. If this feature is off, the hypervisor cannot use hardware-level virtualization, preventing it from operating efficiently. Save changes and restart the computer after enabling the feature.

Check Virtualization in Windows Task Manager

Press Ctrl + Shift + Esc to open the Task Manager. Go to the “Performance” tab and select “CPU”. Look for the “Virtualization” field in the lower-right corner. If it says “Enabled”, virtualization support is active. If it is “Disabled”, enable it in BIOS/UEFI as described above or verify your hardware supports virtualization.

Confirm Hyper-V Installation and Status on Windows

1. Open the Control Panel and navigate to Programs > Turn Windows Features On or Off.
2. Check if “Hyper-V”, “Virtual Machine Platform”, and “Windows Hypervisor Platform” are enabled.
3. If these are unchecked, enable them and restart your system.
4. Alternatively, open PowerShell or Command Prompt and run bcdedit to check the hypervisor launch type. Ensure it is set to “Auto” by entering: bcdedit /set hypervisorlaunchtype auto 

Verify VMware Hypervisor Status

1. Open VMware Workstation or vSphere Client
   Launch VMware software and check if the hypervisor is active by accessing the console. If the interface shows an error, the hypervisor may not be functioning correctly.
2. Validate VT-x or AMD-V in VMware
   Go to “Edit” > “Preferences” > “Processors” and confirm that virtualization engine settings like VT-x or AMD-V are detected and enabled. If they are greyed out or disabled, ensure virtualization is active in BIOS/UEFI.
3. Run a Diagnostic with VMware Logs
   Access the VMware host logs by navigating to the log directory. Look for messages indicating virtualization issues, such as:

Validate VM Creation or Startup Functionality

For both Hyper-V and VMware, attempt to create or start a virtual machine. Errors such as “Hypervisor not found” or “Failed to power on VM” indicate that the hypervisor service is not operational. For VMware, additional error logs can provide insight into specific causes.

How To Identify Hypervisor Errors

Monitor System Logs for Errors

Hypervisor-related errors are often logged in system event logs. On Windows, open the Event Viewer (Win + S, type “Event Viewer”) and navigate to Windows Logs > System. Look for errors or warnings related to “Hyper-V”, “VMMS” (Virtual Machine Management Service), or virtualization.

On VMware, logs are stored in the default directory (e.g., /var/log/ for ESXi) or accessible via the vSphere Client. Check for entries like “Hypervisor failed to initialize” or “VT-x unavailable”.

Use Diagnostic Commands

On Windows, use Command Prompt or PowerShell to run specific commands:

1. Run systeminfo to verify if your system supports Hyper-V. Look for the section “Hyper-V Requirements”. If it states “Yes” for all features, the hardware is compatible. If any features are “No”, hardware or firmware updates may be required.
2. For VMware, use the vSphere CLI or VMware Workstation’s built-in diagnostics. A command like esxcli system stats power-on can reveal CPU-level issues affecting virtualization.

Observe Hypervisor Initialization Behavior

When starting your computer, monitor for error messages related to virtualization. For Hyper-V, errors like “Hypervisor not found” indicate a system misconfiguration. VMware might show “Failed to start the hypervisor” errors directly within the management interface, pointing to potential conflicts or hardware issues.

Inspect VM Start and Resource Allocation Issues

Attempt to start a virtual machine. Errors such as “Virtual machine failed to start” (Hyper-V) or “Failed to power on VM” (VMware) often indicate hypervisor-related problems. These errors can result from insufficient memory, unavailable CPU cores, or disabled virtualization support. Reviewing the error message details provides a clearer understanding of the issue.

Test with Known-Good Virtual Machines

To isolate hypervisor issues, test with a previously functioning virtual machine or import a sample VM. If the VM fails to start, the issue is likely with the hypervisor configuration or environment. On VMware, check if snapshots or linked clones function, as these rely heavily on a properly configured hypervisor.

Verify Hypervisor Service Status

For Hyper-V, open the Services application (Win + R, type “services.msc”) and ensure that “Hyper-V Virtual Machine Management” and related services are running. For VMware, verify that all necessary services (like VMware Workstation Server or vSphere components) are active. Stopped services can cause hypervisor failures.

How To Fix Hypervisor Not Found Errors

Enable Virtualization in BIOS/UEFI

Restart your system and access the BIOS/UEFI settings by pressing the appropriate key (commonly F2, DEL, ESC, or F10) during boot. Navigate to the CPU configuration or advanced settings and enable “Intel Virtualization Technology” (VT-x) or “AMD-V”. Save the changes and restart your computer. This step ensures the hypervisor can access hardware-level virtualization, which is essential for operation.

Re-enable the Hypervisor on Windows

1. Open Command Prompt or PowerShell as an administrator.
2. Run the following command to ensure the hypervisor is enabled: bcdedit /set hypervisorlaunchtype auto
3. Restart your computer.
4. This ensures the Windows Boot Configuration Data (BCD) initializes the hypervisor during startup.

Install or Reinstall Hyper-V or VMware

For Hyper-V on Windows:

1. Go to Control Panel > Programs > Turn Windows Features On or Off.
2. Ensure “Hyper-V”, “Virtual Machine Platform”, and “Windows Hypervisor Platform” are checked.
3. Click “OK” and restart your system to apply changes.

For VMware:

1. Verify your VMware Workstation or ESXi installation. If issues persist, uninstall and reinstall the software.
2. Download the latest version from VMware’s website to ensure compatibility with your system.

Check for Conflicting Software

Disable or uninstall third-party applications like VirtualBox, Docker, or certain antivirus programs that may conflict with the hypervisor. For example, VirtualBox may lock virtualization resources, preventing the hypervisor from starting. Restart your system after making these changes.

Update Drivers and Firmware

1. Download and install the latest drivers for your CPU and chipset from the manufacturer’s website (Intel, AMD, or your motherboard vendor).
2. Check for BIOS/UEFI updates that address virtualization bugs. Updating firmware can resolve known compatibility issues that cause hypervisor errors.

Validate and Repair System Files

Corrupt system files may prevent the hypervisor from initializing. Run the following commands in Command Prompt as an administrator:

1. Run System File Checker (SFC): sfc /scannow
2. Run Deployment Image Servicing and Management (DISM) to repair Windows: dism /online /cleanup-image /restorehealth

These tools scan for and repair corrupt system files, restoring the hypervisor’s functionality.

Reconfigure Boot Settings

Sometimes, boot settings can interfere with the hypervisor. Reset the boot configuration by running these commands:

1. Reset BCD: bcdedit /deletevalue hypervisorlaunchtype
2. Restart your system and re-enable the hypervisor using the bcdedit /set hypervisorlaunchtype auto command.

How To Fix Blue Screen of Death in Your Hypervisor on Windows

A Blue Screen of Death (BSOD) involving your hypervisor often stems from system-level conflicts, driver issues, or hardware instability. Here’s how to fix it while addressing the most common causes.

Common Causes of Hypervisor BSODs

1. Driver Conflicts: Outdated or incompatible drivers, especially for graphics or network adapters, can interfere with the hypervisor’s low-level operations.
2. Hardware Failures or Instability: Overclocked processors, faulty RAM, or insufficient cooling can destabilize the system, causing BSODs during hypervisor operations.
3. Software Conflicts: Certain applications, including virtualization tools like VirtualBox or KVM, can conflict with Hyper-V or VMware, leading to crashes.
4. Corrupt System Files: Damaged system or hypervisor files may cause kernel-level errors, resulting in BSODs.
5. Incompatible System Updates: Recently installed updates, especially for Windows or firmware, can conflict with the hypervisor.

Analyze the BSOD Error Code

1. Note the stop code displayed on the BSOD screen. Common hypervisor-related codes include:
   • CRITICAL_STRUCTURE_CORRUPTION: Indicates hardware or system-level conflicts.
   • HYPERVISOR_ERROR: Points to issues in the hypervisor kernel.
2. Use Windows Debugging Tools or a tool like BlueScreenView to analyze minidump files located in C:\Windows\Minidump. These logs can help pinpoint the root cause.

Update or Reinstall Drivers

1. Open Device Manager (Win + X > Device Manager) and check for devices with yellow warning signs.
2. Update drivers for critical components, such as the graphics card, chipset, and network adapter. Download updates directly from the manufacturer’s website to avoid compatibility issues.
3. If the problem persists, uninstall the problematic driver and reinstall it using the latest version.

Disable Conflicting Software

1. Uninstall or temporarily disable other virtualization software like VirtualBox, Docker, or third-party hypervisors. These can max out memory and cause the hypervisor to fail.
2. Check antivirus or security software settings. Disable any features that may interfere with hardware virtualization.

Verify and Repair Hypervisor Installation

For Hyper-V:

1. Go to Control Panel > Programs > Turn Windows Features On or Off.
2. Uncheck “Hyper-V”, restart your computer, then re-enable it. This will reinstall the Hyper-V components.

For VMware:

1. Uninstall VMware Workstation or vSphere, then reinstall the latest version from VMware’s website.
2. Check VMware logs for errors (stored in default log directories) to identify specific causes.

Repair Corrupt System Files

1. Open Command Prompt as an administrator.
2. Run sfc /scannow to repair corrupt system files.
3. Use DISM to fix deeper system image issues: dism /online /cleanup-image /restorehealth
4. Restart your system after repairs.

Adjust Overclocking or Hardware Settings

1. Reset overclocked CPU or RAM settings to default in BIOS/UEFI. Overclocking can destabilize the hypervisor and lead to BSODs.
2. Run memory diagnostics by typing mdsched in the Windows search bar and selecting “Restart now and check for problems”. Replace faulty RAM if errors are detected.

Roll Back or Update System Software

1. If the BSOD started after a recent update, roll it back: Go to Settings > Update & Security > View Update History > Uninstall Updates and remove the recent update.
2. If rolling back doesn’t work, check for new updates that may include patches for hypervisor issues.

Disable Hypervisor Temporarily for Testing

1. Run the following command in Command Prompt as an administrator: bcdedit /set hypervisorlaunchtype off
2. Restart your system to see if disabling the hypervisor resolves the BSOD. This helps confirm whether the hypervisor is the root cause.
3. Re-enable it later by running: bcdedit /set hypervisorlaunchtype auto

Most Common Hypervisor Errors With Fixes

Hypervisor Not Found

Cause: This error often occurs due to virtualization being disabled in BIOS/UEFI, an incompatible CPU, or conflicting software.
Fix:

1. Enable Intel VT-x or AMD-V in the BIOS/UEFI settings.
2. Ensure your CPU supports virtualization by checking the manufacturer’s specifications.
3. Uninstall conflicting software like VirtualBox or Docker.
4. Run bcdedit /set hypervisorlaunchtype auto in Command Prompt and restart your system.

Virtual Machine Failed to Start

Cause: Insufficient system resources, misconfigured virtual machine settings, or corrupted hypervisor files can prevent virtual machines from starting.
Fix:

1. Verify adequate CPU, RAM, and disk space allocation for the virtual machine.
2. Check if Hyper-V or VMware services are running (services.msc on Windows).
3. Repair system files by running sfc /scannow in Command Prompt.

VT-x Is Not Available

Cause: This error occurs if virtualization is disabled in BIOS/UEFI, the processor lacks virtualization support, or another hypervisor is monopolizing hardware-level virtualization.
Fix:

1. Enable virtualization in BIOS/UEFI.
2. Uninstall or disable other hypervisors like VMware or VirtualBox.
3. Update BIOS/UEFI firmware to ensure full support for virtualization features.

Blue Screen of Death (BSOD) Related to Hypervisor

Cause: Driver conflicts, hardware instability, or system file corruption can trigger a BSOD.
Fix:

1. Update all drivers, especially for the CPU, GPU, and network adapter.
2. Run memory diagnostics (mdsched) to identify and replace faulty RAM.
3. Use sfc /scannow and dism /online /cleanup-image /restorehealth to repair system files.
4. Roll back recent updates if the error began after a system update.

Failed to Power On Virtual Machine

Cause: Misconfigured virtual machine settings or conflicts with the hypervisor can cause this error.
Fix:

1. Verify that the allocated CPU and memory match the available system resources.
2. Ensure that your hypervisor is active (bcdedit /set hypervisorlaunchtype auto for Hyper-V).
3. Restart VMware or Hyper-V services.

Hyper-V Not Installed or Missing Features

Cause: The required Windows features may not be installed or were corrupted during installation.
Fix:

1. Navigate to Control Panel > Programs > Turn Windows Features On or Off and enable “Hyper-V”, “Windows Hypervisor Platform”, and “Virtual Machine Platform”.
2. Restart the system to apply changes.
3. Reinstall Hyper-V components if the issue persists.

Cannot Install Hypervisor Due to Conflicting Updates

Cause: Older Windows updates or firmware issues can block the installation of Hyper-V or VMware hypervisors.
Fix:

1. Check for updates via Settings > Update & Security > Windows Update and install the latest patches.
2. Uninstall conflicting updates via Control Panel > Programs > View Installed Updates if the error appeared after a specific update.

Hypervisor Service Not Running

Cause: The hypervisor’s core services are not running or have failed to start.
Fix:

1. Open Services (services.msc) and start the “Hyper-V Virtual Machine Management” or related VMware services.
2. Set the service to “Automatic” to ensure it starts on boot.
3. Restart the computer to apply the changes.

Hypervisor Best Practices To Manage Hypervisors

1. Allocate Resources Strategically Assign appropriate amounts of CPU, memory, and disk resources to virtual machines (VMs) based on their workload. Overcommitting resources can cause system instability and degrade performance across all VMs. Use dynamic memory and CPU allocation when supported to optimize utilization.
2. Enable Snapshots for Configuration Changes Take snapshots of your VMs before applying updates or making significant configuration changes. Snapshots allow you to roll back to a stable state if issues arise. However, manage snapshots efficiently to avoid consuming excessive disk space.
3. Isolate Hypervisor Networks For security and performance, separate the network used by the hypervisor and its management console from the network accessed by VMs. This prevents unauthorized access to the hypervisor and reduces network congestion.
4. Regularly Update Hypervisor Software Keep your hypervisor platform (e.g., VMware ESXi, Microsoft Hyper-V) updated with the latest patches and releases. Updates often address security vulnerabilities, performance issues, and compatibility with new hardware.
5. Implement Role-Based Access Control (RBAC) Restrict access to the hypervisor management console based on roles. Only administrators should have full control, while end users or operators should have limited permissions. This minimizes the risk of accidental or malicious changes to the hypervisor environment.
6. Perform Regular Backups Back up both your hypervisor configuration and the virtual machines running on it. Use tools compatible with your platform to automate and schedule backups. Regular backups ensure quick recovery in case of hardware failures or data corruption.
7. Monitor System Health and Performance Use built-in monitoring tools or tools like SolarWinds Virtualization Manager to track the health and performance of the hypervisor and its VMs. Monitor metrics such as CPU, memory, disk I/O, and network traffic. Set alerts to notify administrators of potential issues before they escalate.
8. Optimize VM Storage Use storage technologies optimized for virtualization, such as thin provisioning and SSD caching. Thin provisioning reduces wasted storage space by allocating resources dynamically, while SSD caching improves I/O performance for frequently accessed data.
9. Test Disaster Recovery Plans Simulate disaster scenarios to test your backup and recovery procedures. This ensures that your systems can be restored quickly and effectively in case of hardware failures, data corruption, or cyberattacks.