VBoxMouse.sys BSOD

Guide to preventing and fixing Blue Screen of Death (BSOD) crashes caused by vboxmouse.sys driver conflicts.

The Problem

Users may experience a sudden BSOD (Blue Screen of Death) when:

• Connecting or disconnecting a USB mouse or USB receiver.
• Waking the computer from sleep.
• Launching VirtualBox.

Error Message: SYSTEM_THREAD_EXCEPTION_NOT_HANDLED (vboxmouse.sys)

The Cause

This error usually happens because VirtualBox Guest Additions have been installed on the Host OS (your physical computer) instead of the Guest OS (the virtual machine).

• Guest Additions: Drivers meant to run inside the virtual machine to improve performance and integration.
• Host OS: Your main Windows installation.

When installed on the host, the vboxmouse.sys driver conflicts with your physical mouse driver.

Solution 1: Uninstall Guest Additions from Host

1. Boot into Safe Mode if you cannot boot normally (see instructions below).
2. Go to C:\Program Files\Oracle\VirtualBox Guest Additions.
3. Run uninstall.exe or use Control Panel > Programs and Features.
4. Look for "Oracle VM VirtualBox Guest Additions" in the list.
5. Uninstall it.
6. Restart your computer.

Solution 2: Manually Delete the Driver

If you can't uninstall it normally:

1. Open File Explorer and navigate to C:\Windows\System32\drivers.
2. Find the file vboxmouse.sys.
3. Rename it to vboxmouse.sys.bak or simply delete it.
4. Restart your computer.

How to Boot into Safe Mode (If Crashing on Boot)

1. Interrupt the normal startup process 3 times (by holding the power button to turn it off as soon as the Windows logo appears) to trigger Automatic Repair.
2. Go to Advanced options > Troubleshoot > Advanced options > Startup Settings.
3. Click Restart.
4. Press 4 or F4 on your keyboard to enable Safe Mode.

Correct Usage of Guest Additions

Do NOT run the VBoxGuestAdditions.iso on your host Windows desktop.

Correct way:

1. Start your Virtual Machine.
2. In the VM window menu, click Devices.
3. Click Insert Guest Additions CD image....
4. Open File Explorer inside the VM.
5. Run the installer from the virtual CD drive (usually D: or E:).