How to Fix Windows Sandbox Failed to Initialize or Won't Start on Windows
Windows Sandbox failing to start? "Windows Sandbox failed to initialize" error? Sandbox crashes on launch? Hypervisor not running for Sandbox? Fix Windows Sandbox startup failures.
Symptoms
You might be experiencing this problem if you notice:
- •"Windows Sandbox failed to initialize" error on launch
- •Sandbox window opens briefly then closes
- •Error: "Hypervisor is not running" when starting Sandbox
- •Sandbox stuck on "Starting Windows Sandbox" indefinitely
- •Sandbox is grayed out or missing from Start menu
- •Sandbox worked before but stopped after Windows Update
Common Causes
- ⚠Virtualization (VT-x/AMD-V) not enabled in BIOS
- ⚠Hyper-V or Windows Hypervisor Platform not enabled
- ⚠Windows Sandbox optional feature not installed
- ⚠Conflicting virtualization software (VirtualBox, VMware)
- ⚠Sandbox base image corrupted
- ⚠Insufficient RAM or disk space for sandbox VM
Solutions
Solution 1: Enable Required Features
- 1Windows Sandbox requires specific features enabled:
- 2Settings → Apps → Optional features → More Windows features
- 3Or: CMD as Admin: optionalfeatures.exe
- 4Enable ALL of these:
- 5☑ Windows Sandbox
- 6☑ Hyper-V (or at minimum: Hyper-V Platform)
- 7☑ Windows Hypervisor Platform
- 8☑ Virtual Machine Platform
- 9Click OK → restart when prompted
- 10Also enable virtualization in BIOS:
- 11Restart → enter BIOS (Del/F2/F10/F12 during boot)
- 12Find: Intel VT-x or AMD-V / SVM → Enable
- 13Save and exit BIOS
Solution 2: Fix Hypervisor Issues
- 1Verify hypervisor is running:
- 2CMD as Admin: systeminfo | find "Hypervisor"
- 3Should show: "A hypervisor has been detected"
- 4If not: bcdedit /set hypervisorlaunchtype auto
- 5Restart PC
- 6If VMware or VirtualBox installed:
- 7These can conflict with Hyper-V based Sandbox
- 8VirtualBox 6.1+: use VBoxManage setextradata global "VBoxInternal/NEM/UseRing0Runloop" 0
- 9VMware 15.5+: supports side-by-side with Hyper-V
- 10Older versions: may need to choose one or the other
Solution 3: Reset Windows Sandbox
- 1Remove and reinstall Sandbox:
- 2CMD as Admin:
- 3dism /online /disable-feature /featurename:Containers-DisposableClientVM /norestart
- 4Restart PC
- 5dism /online /enable-feature /featurename:Containers-DisposableClientVM /all /norestart
- 6Restart PC again
- 7Clear sandbox base image cache:
- 8Delete contents of: C:\ProgramData\Microsoft\Windows\Containers\BaseImages
- 9Sandbox will recreate the base image on next launch
- 10Ensure at least 4GB RAM free and 10GB disk space
- 11sfc /scannow if system files may be corrupted
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