Hyper V Virtual Machine Not Starting

What the Error Code Means

When a Hyper-V virtual machine fails to start, the system typically displays a message with an error code, such as:

• 0x80070490 — Access error (administrator privileges required).
• 0x80070005 — General access denied.
• 0x80070057 — Invalid parameter (often a memory or disk configuration issue).
• 0x8007000d — Corrupted configuration data.

The error may appear on first startup, after VM import, or when attempting to start from a powered-off state. Often, the VM state gets stuck on "Starting" or "Stopping," and corresponding entries appear in the Hyper-V logs (C:\Windows\Logs\Hyper-V).

Common Causes

1. Insufficient Access Permissions
   The user account lacks permissions to read/write in the VM's file folder or to manage Hyper-V.
2. Resource Conflict
   Insufficient RAM, CPU overload, or lack of disk space for a dynamically expanding VHDX file.
3. VM Configuration Corruption
   .vmcx (configuration) or .vmrs (state) files are corrupted, especially after an improper shutdown.
4. Virtual Switch Issues
   The VM's network adapter is bound to a non-existent or non-functional virtual switch.
5. Driver or Antivirus Conflict
   Some antivirus software (e.g., Avast, Kaspersky) or third-party drivers block the hypervisor.
6. Version Incompatibility
   The VM was created in a newer Hyper-V version (e.g., Windows 11) and is attempting to run on an older one (Windows 10).
7. Disabled Hyper-V Services
   The Hyper-V Virtual Machine Management or Hyper-V Host Compute Service services are not running.

Solution 1: Run Hyper-V Manager as Administrator

Most often, the issue is resolved by simply running the Manager with elevated privileges.

1. Close Hyper-V Manager if it is open.
2. Find the Hyper-V Manager shortcut in the Start menu or on the taskbar.
3. Right-click → Run as administrator.
4. Try starting the virtual machine.

If this worked, configure the shortcut properties: Shortcut tab → Advanced → check Run as administrator.

Solution 2: Check and Fix NTFS Permissions

Hyper-V requires full access to the virtual machines folder.

1. Open File Explorer and navigate to:
   C:\Users\Public\Documents\Hyper-V\Virtual Machines
2. Right-click the folder with your VM's name (files .vmcx, .vmrs) → Properties → Security.
3. Click Edit → Add.
4. In "Enter the object names to select," type:
   Administrators → Check Names → OK.
5. Select the "Administrators" group and check Full control.
6. Click Apply and OK.
7. Repeat for the C:\Users\Public\Documents\Hyper-V (Hyper-V root) folder.
8. Restart Hyper-V Manager and try to start the VM.

Check Permissions via PowerShell (Alternative)

# Run PowerShell as Administrator
$vmPath = "C:\Users\Public\Documents\Hyper-V\Virtual Machines"
$acl = Get-Acl $vmPath
$rule = New-Object System.Security.AccessControl.FileSystemAccessRule("Administrators","FullControl","ContainerInherit, ObjectInherit","None","Allow")
$acl.SetAccessRule($rule)
Set-Acl -Path $vmPath -AclObject $acl
Write-Host "Permissions updated. Restart Hyper-V Manager."

Solution 3: Configure Memory and CPU

Incorrect allocated memory values are a common cause of failure.

1. In Hyper-V Manager, right-click the virtual machine → Settings.
2. Under Memory:
   • Uncheck Enable Dynamic Memory (temporarily).
   • Set Static memory to a value less than the host's free RAM (e.g., 2048 MB).
   • Click Apply.
3. Under Processor:
   • Reduce the number of virtual processors (e.g., to 2).
   • Uncheck Enable processor compatibility for migration (if you don't need to move the VM between hosts).
4. Click OK and try to start the VM.

⚠️ Important: Do not allocate more than 80% of the host's total RAM to the VM. Otherwise, the system may be unable to start the process.

Solution 4: Disable the Virtual Network Adapter

A problematic network driver or virtual switch can block startup.

1. In the VM's settings, go to Network Adapter.
2. Under Virtual switch, select Not Connected from the list.
3. Click Apply.
4. Try to start the virtual machine.

If the VM starts, the issue is with the network configuration:

• Recreate the virtual switch (in Hyper-V Manager menu: Actions → Virtual Switch Manager).
• Ensure the selected physical adapter is not used by other programs (e.g., VPN clients).

Solution 5: Reinstall Hyper-V Components

Corrupted Hyper-V system files will be restored upon component reinstallation.

1. Open Control Panel → Programs and Features → Turn Windows features on or off.
2. Find Hyper-V and uncheck all boxes.
3. Click OK and wait for completion.
4. Restart the computer.
5. Open the features again, check the boxes:
   • Hyper-V
   • Hyper-V Management Tools
   • Hyper-V Platform
6. Click OK and restart again.
7. Launch Hyper-V Manager and check the VM.

Using PowerShell for Reinstallation

# Run PowerShell as Administrator
Disable-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V-All -NoRestart
Restart-Computer
Enable-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V-All -All -NoRestart
Restart-Computer

Solution 6: Restore Configuration Files

If the .vmcx or .vmrs files are corrupted, create a new configuration.

1. Back up the entire VM folder (all files).
2. In Hyper-V Manager, click Actions → New → Virtual Machine.
3. Specify the same name, but select Generation 1 (if the VM was Generation 1) or Generation 2 (if it was Generation 2).
4. On the Connect Virtual Hard Disk step, select Use an existing virtual hard disk and point to your .vhdx file.
5. Complete the wizard and try to start the new VM.

💡 Tip: If the VM was Generation 2 but won't start, create a Generation 1 VM with the same VHDX—this bypasses some UEFI limitations.

Solution 7: Clear Logs and Reset State

Sometimes clearing temporary files and resetting the VM state helps.

1. Close Hyper-V Manager.
2. Delete the .vmrs (state) and any temporary .vhdx files in the VM folder. Do NOT delete .vmcx or the primary .vhdx!
3. Open Services (services.msc), find Hyper-V Virtual Machine Management → restart the service.
4. Launch Hyper-V Manager and try again.

Prevention

• Regularly update Windows — many Hyper-V issues are fixed in cumulative updates.
• Do not manually edit .vmcx files — use only Hyper-V Manager or PowerShell (Set-VM).
• Allocate static memory for critical VMs to avoid dynamic memory conflicts.
• Use Hyper-V-compatible antivirus or configure exclusions for these folders:
  • C:\Users\Public\Documents\Hyper-V
  • C:\ProgramData\Microsoft\Windows\Hyper-V
• Back up virtual machines before migration or system updates.
• Check version compatibility when importing VMs: export from the source Hyper-V as a VM copy (not an export configuration).

If none of these solutions help, check the Windows Event Logs (Event Viewer → Applications and Services Logs → Microsoft → Windows → Hyper-V) for the exact error code.