Switching Mac OS to Single User Mode

Products

• VMware Desktop Hypervisor

Issue/Introduction

This article describes how to switch into Single User Mode on a Mac OS X operating system. Single User Mode is useful when troubleshooting problems where it is suspected that something may be causing unexpected operating system behavior. Additionally, it is used to troubleshoot Mac OS failing to boot normally.

Symptoms:
A Mac OS X operating system:

• Has failed
• Has stopped responding
• Keeps rebooting for no apparent reason
• Has performance problems
• Is slow
• Is experiencing network problems

Environment

VMware Fusion 10.x
VMware Fusion 5.x
VMware Fusion Pro 11.x
VMware Fusion 11.x
VMware Fusion 8.x
VMware Fusion 7.x
VMware Fusion 6.x
VMware Fusion 2.x
VMware Fusion 3.x
VMware Fusion 1.x
VMware Fusion 4.x

Resolution

To switch into Single User Mode:

Note: Single User Mode significantly limits the functionality of the operating system. You do not have access to any portion of the normal Mac OS graphical interface. VMware recommends that you only use Single User Mode if you have experience with the operating system and already know how to use this Mac OS feature.

1. Shut down and then power on the computer.
2. Immediately press and hold Command + S.
3. Release Command + S when you are at a shell prompt.
   
   Note: To leave Single User Mode type exit and press Enter.

If you are attempting to start up a Mac Server OS virtual machine in Single User Mode, Command + S attempts to take a snapshot of the virtual machine. Therefore, you must remap Command + S to be sent a different key stroke.

You can remap a different key combination on the host Mac to send Command + S to the virtual Mac. Shift + Command + S is already assigned, but Option + Command + S is a valid alternative.

To remap the keys:

1. Open Fusion.
2. Go to VMware Fusion > Preferences > Keyboard & Mouse > Key Mappings.
3. Click the + button to add a shortcut.
4. Under From:, select Option, Command, and S (from the dropdown).
5. Under To:, select the Windows key and S (from the dropdown).
   
   Note: In newer versions of Mac OS X, you need to type S in the right text field.
    
6. Click OK.
7. Close the Preferences window.
8. Shut down any open virtual machines.
9. Quit and reopen Fusion.