Safe Mode in Windows 2000/XP/2003
What are the Safe Mode options? When should I use them?
If you are unable to start your system by using Last Known Good Configuration, Windows XP Professional, Windows 2000 and Windows Server 2003 provides safe mode, a startup option that disables startup programs and nonessential services to create an environment useful for troubleshooting and diagnosing problems.
In safe mode, Windows XP/2000/2003 starts a minimal set of drivers that the operating system needs to function. Support for devices such as audio devices, most USB devices, and IEEE 1394 devices is disabled to reduce the variables that you need to account for when diagnosing the cause of startup problems, Stop messages, or system instability.
Logging on to the computer in safe mode does not update Last Known Good Configuration information. Therefore, if you log on to your computer in safe mode and then decide you want to try Last Known Good Configuration, the option to do so is still available.
Essential drivers and system services enabled in safe mode include the following:
- Drivers for serial or PS/2 mouse devices, standard keyboards, hard disks, CD-ROM drives, and standard VGA devices. Your system firmware must support universal serial bus (USB) mouse and USB keyboard devices in order for you to use these input devices in safe mode.
- System services for the Event Log, Plug and Play, remote procedure calls (RPCs), and Logical Disk Manager.
Enabling only components needed for basic functionality allows the operating system to start in the following situations:
- The computer consistently stops responding: You can restart the operating system in safe mode and use the tools described in this appendix to diagnose and resolve problems.
- The computer starts with a blank or distorted video display: You can start your computer in safe mode and then use Control Panel to select video adapter settings that are compatible with your monitor. New settings take effect when you restart the computer.
- The computer does not start normally after you install new hardware or software: If recently installed hardware or software prevents you from starting Windows XP Professional in normal mode, you can use safe mode to uninstall software, or to remove or roll back device drivers.
Safe mode helps you diagnose problems. If a symptom does not reappear when you start in safe mode, you can eliminate the default settings and minimum device drivers as possible causes. If a newly added device or a changed driver is causing problems, you can use safe mode to remove the device or reverse the change.
There are circumstances where safe mode will not be able to help you, such as when Windows system files that are required to start the system are corrupted or damaged. In this case, the Recovery Console may help you.
Safe Mode also bypasses startup programs. Bypassing startup programs reduces system complexity and enables you to see whether a startup program is the source of the problem.
In safe mode, the operating system does not run network-based startup programs. To enable network logon scripts in safe mode, select Safe Mode with Networking on the Windows Advanced Options Menu.
To start your computer in safe mode:
- Remove all floppy disks and CDs from your computer, and then restart your computer.
- When prompted, press F8. If Windows XP Professional starts without displaying the Please select the operating system to start menu, restart your computer. Press F8 after the firmware POST process completes, but before Windows displays graphical output.
- From the Windows Advanced Options Menu, select a safe mode option listed in the following list:
(Windows 2000 Boot menu screenshot)
Safe Mode: Loads the minimum set of device drivers and system services required to start Windows XP/2000/2003. User specific startup programs do not run.
Safe Mode with Networking: Includes the services and drivers needed for network connectivity. Safe mode with networking enables logging on to the network, logon scripts, security, and Group Policy settings. Nonessential services and startup programs not related to networking do not run.
Safe Mode with Command Prompt: Starts the computer in safe mode, but displays the command prompt rather than the Windows GUI interface.
Enable Boot Logging: Creates a log file (Ntbtlog.txt) in the systemroot folder, which contains the file names and status of all drivers loaded into memory. Systemroot is an environment variable that can vary from one system running Windows XP/2000/2003 to another.
Enable VGA Mode: Starts the computer in standard VGA mode by using the current video driver. This option helps you recover from distorted video displays caused by using incorrect settings for the display adapter or monitor.
Last Known Good Configuration: Restores the registry and driver configuration in use the last time the computer started successfully.
Debugging Mode: Starts Windows XP/2000/2003 in kernel debugging mode, which allows you to use a kernel debugger for troubleshooting and system analysis.
Start Windows Normally: Starts Windows XP/2000/2003 in normal mode.
Reboot: Restart the computer.