Fixing WSL2 "Access Denied" Error on Windows After Reboot

If your WSL2 suddenly throws an error like:

Failed to attach disk 'F:\ext4.vhdx' to WSL2: Access is denied.
Error code: Wsl/Service/CreateInstance/MountDisk/HCS/E_ACCESSDENIED

This usually happens because Windows lost permissions to access your WSL2 disk image (ext4.vhdx). Here's a quick fix:

Step-by-Step Solution

1. Open PowerShell as Administrator.
2. Run these commands (replace F:\ext4.vhdx with your actual VHDX file location):

   $VhdPath = "F:\ext4.vhdx"
   wsl --shutdown
   icacls $VhdPath /grant:r 'SYSTEM:(F)' 'Administrators:(F)' /inheritance:e
   icacls $VhdPath /grant '*S-1-5-83-0:(M)'
   attrib +R $VhdPath

• This sets permissions properly for SYSTEM, Administrators, and WSL2 Virtual Machines.
• The attrib +R command makes the file read-only, preventing antivirus or backup software from interfering with permissions.

3. Restart WSL2 by simply running:

   wsl

Confirm the Fix

To double-check permissions:

icacls $VhdPath

You should see entries for SYSTEM, Administrators, and a group SID starting with S-1-5-83-0.

That's it! Your WSL2 environment should now work smoothly after reboots or updates.