In Windows, what is Safe Mode used for and why?

While Windows is a versatile and powerful operating system, there are

times that it can be frustrating. This frustration is particularly

evident when you install a new software application or add drivers for

some new hardware. Suddenly, the computer crashes or locks up. You

reboot the computer and it loads a strange looking Windows desktop

with the words Safe Mode in the four corners. What is this?



Safe Mode is a special way for Windows to load when there is a

system-critical problem that interferes with the normal operation of

Windows. The purpose of Safe Mode is to allow you to troubleshoot

Windows and try to determine what is causing it to not function

correctly. Once you have corrected the problem, then you can reboot

and Windows will load normally.



There are several things that happen when Windows boots in Safe Mode that differ



Safe Mode does not run the autoexec.bat or config.sys files.



Most device drivers are not loaded. A device driver is the software

that Windows uses to interact with a piece of hardware, such as a

printer or scanner.



Instead of the normal graphics device driver, Safe Mode uses standard

VGA graphics mode. This mode is supported by all Windows-compatible

video cards.



Himem.sys, which is normally loaded as part of the config.sys script,

is loaded with the /testmem:on switch. This switch tells the computer

to test the extended memory



Safe Mode checks the msdos.sys file for information on where to find

the rest of the Windows files. If it finds the files, it proceeds to

load Windows in Safe Mode with the command win /d:m. If it does not

find the Windows files, it will run command.com to



Windows boots using a batch file called system.cb instead of the

standard system.ini file. This file loads the Virtual Device Drivers

(VxDs) that Windows uses to communicate with the standard parts of the

computer.



Windows now loads the regular system.ini file plus win.ini and

Registry settings. It skips the [Boot] (except for the shell and

device lines) and [386Enh] sections of system.ini and does not load or

run any programs listed in win.ini.



The Windows desktop loads up in 16 colors and at a resolution of 640 x

480 with the



Safe Mode starts up automatically if Windows does not boot on the

previous attempt. You can also invoke Safe Mode by pressing F5 or by

pressing F8 and selecting it from



So what should you do if your computer boots to Safe Mode? First, try

to determine what has changed on your system that could have caused

Windows to fail to boot properly. If you have added any kind of

hardware, go to the Control Panel and remove it and uninstall the

software driver for that device. Then attempt a reboot. If Windows

boots properly, you can be reasonably certain that there was some type

of conflict with



Use this same method if you have loaded a new game or application

sometime recently. Go to the Control Panel, click on Add/Remove

Programs and remove the software. Try a reboot and hopefully you will

get a normal Windows boot.



If the problem is definitely not new hardware or software, then you

most likely have a corrupted Registry. In this case, you will quite

likely have to perform a new installation



See the next page to learn more about safe mode and operating systems.