Troubleshooting Windows 95 Using Safe Mode (156126)


The information in this article applies to:

  • Microsoft Windows 95
  • Microsoft Windows 95 OEM Service Release 2
This article was previously published under Q156126

SUMMARY

IMPORTANT: This article contains information about editing the registry. Before you edit the registry, you should first make a backup copy of the registry files (System.dat and User.dat). Both are hidden files in the Windows folder.

Starting Windows 95 in Safe mode can help you resolve issues that occur when you start Windows 95 normally. These issues include (but are not limited to):
  • Setup hangs during the first reboot
  • Error messages
  • Hanging
  • Loss of functionality

MORE INFORMATION

Starting Windows 95 in Safe mode bypasses the current real-mode configuration and loads a minimal protected-mode configuration, disabling Windows 95 device drivers and using the standard VGA display adapter.

If the issue does not occur in Safe mode, you may be experiencing a conflict with hardware settings, real-mode configuration issues, incompatibilities with legacy Windows programs or drivers, or registry damage.

For a description of the events that occur when you boot Windows 95 in Safe mode, see the following article in the Microsoft Knowledge Base:

122051 How Windows 95 Performs a Safe Mode Start

PREPARING TO TROUBLESHOOT IN SAFE MODE

The procedures in the following sections describe steps to troubleshoot configurations in which Safe mode resolves an issue with Windows 95. Many of these troubleshooting steps require changes to system configuration files. These changes are not intended to be permanent; they should be used as techniques for isolating the conflict that resulted in an issue with the normal configuration.

The examples in this article assume that Windows 95 has been installed in the Windows folder on drive C. Adjust the syntax as required by your configuration.

Before you begin making changes, you should create an Emergency Boot Disk (EBD) if you do not already have one. You can use the EBD to restart the computer and edit the configuration files if any changes you make cause the computer to hang.

To create an Emergency Boot Disk, follow these steps:
  1. In Control Panel, double-click Add/Remove Programs.
  2. Click the Startup Disk tab, and then click Create Disk.
Once you have an EBD, shut down Windows 95, insert the EBD in drive A, and restart the computer. Make sure the computer can boot using the EBD. Restart the computer normally.

Troubleshooting the Windows 95 configuration files may require that the files be edited. You can use the MS-DOS text editor or System Configuration Editor to edit these files.

To use the MS-DOS text editor, type edit.com at a command prompt, and then choose the Open command on the File menu to open the file you want.

To use System Configuration Editor, click the Start button, click Run, type sysedit in the Open box, and then click OK. Click the file you want to edit on the Window menu.

TROUBLESHOOTING

The Safe-mode troubleshooting steps are broken into the following sections:
  • Issues with the real-mode configuration
  • Windows 95 command-line switches
  • Windows configuration files and programs started automatically at startup
  • Protected-mode device drivers
  • Changing the video driver to the standard VGA display driver
  • Registry damage
  • If the problem persists

ISSUES WITH THE REAL-MODE CONFIGURATION

Windows 95 bypasses the Config.sys and Autoexec.bat files in Safe mode. A real-mode device driver or terminate-and-stay-resident program (TSR) loading in one of these files may conflict with Windows 95, leading to the issues you are experiencing during a normal boot. The following steps can help you determine if this is the case.

Test the Real-Mode Configuration

  1. Restart the computer. When you see the "Starting Windows 95" message, press the F8 key, and then choose Command Prompt Only from the Startup menu.

    NOTE: If the Windows 95 graphical user interface (GUI) loads, edit the Autoexec.bat file and remove or disable the "win" line.
  2. Start Windows 95 with a minimal set of Windows drivers by typing the following line:

    win /d:m

    NOTE: If networking components are required to start Windows 95, type the following line instead of the line above:

    win /d:n

If the issue does not occur when you start Windows 95 in this manner, you have determined that the real-mode and protected-mode configuration conflict.

If the issue persists, the contents of the Config.sys or Autoexec.bat file may be at fault. You have determined that a conflict exists with the real-mode configuration, and you should perform a clean boot of the real- mode configuration.

Clean Real-Mode Boot

Windows 95 does not require a Config.sys or Autoexec.bat file. These files are necessary only for backward compatibility. If you do not need these files, rename them and restart your computer. For example, rename the Autoexec.bat file to Autoexec.bak, and rename the Config.sys file to Config.bak.

If the Config.sys and Autoexec.bat files are required, perform a clean boot of the real-mode configuration with the required drivers. To do so, follow these steps:
  1. Restart your computer. When you see the "Starting Windows 95" message, press the F8 key, and then choose Step-By-Step Confirmation from the Startup menu.
  2. Load the following items when prompted:
    • Dblspace driver (if the hard disk is compressed).
    • Do not process the Config.sys file.
    • Himem.sys.
    • Ifshlp.sys.
    • Dblbuff.sys (only if prompted).
    • Do not process the Autoexec.bat file.
    • Load the Windows 95 graphical user interface (GUI), choosing to load all Windows drivers.
If the clean boot of your real-mode configuration eliminates the issue, isolate the conflict with a TSR or real-mode device driver using the step- by-step confirmation function.

WINDOWS 95 COMMAND-LINE SWITCHES

Starting Windows 95 with command line switches is an effective method for isolating issues with your configuration. The switches should be used for troubleshooting only; use the information to modify your existing configuration and eliminate the conflict.
  1. Follow the instructions for a clean real-mode boot in the "Clean Real- Mode Boot" section above, but do not load the Windows GUI.
  2. Start Windows 95 using the troubleshooting command-line switches by typing the following line:

    win /d:fsvx

Description of Command-Line Switches

/D - Used for troubleshooting when Windows 95 does not start correctly.

F - Disables 32-bit disk access. This is equivalent to disabling the hard disk controller(s) in Device Manager.

S - Specifies that Windows 95 should not use ROM address space between F000:0000 and 1 MB for a break point.

V - Specifies that the ROM routine will handle interrupts from the hard disk controller. This is equivalent to the System.ini file setting of "VirtualHDIRQ=FALSE."

X - Excludes all of the adapter area from the range of memory that Windows 95 scans to find unused space. This is equivalent to the System.ini file setting of "EMMExclude=A000-FFFF." If this switch resolves the issue, you may have a conflict in the upper memory area (UMA) that requires an Exclude statement.

NOTE: Each of the System.ini file entries referenced above belongs in the [386Enh] section of the System.ini file.

WINDOWS CONFIGURATION FILES AND PROGRAMS STARTED AUTOMATICALLY

Windows 95 includes several methods for loading programs automatically. Starting in Safe mode prevents any programs from being started automatically.

Windows 95 includes a Win.ini and System.ini file for backward compatibility with legacy programs and device drivers. Upgrading a previous installation of Windows 3.x to Windows 95, as well as adding software, can lead to conflicts within the Windows configuration files.

Determine If Issue Is Related to Program Starting at Startup

Load Windows 95 by booting to a command prompt and starting Windows 95 by typing win, holding down the SHIFT key for the duration of the boot. This prevents any programs from loading automatically at startup.

If the issue is resolved by preventing programs from loading at startup, investigate the following possible sources:

The Winstart.bat File

The Winstart.bat file is used to load TSRs that are required for Windows- based programs and are not needed in MS-DOS sessions.

For more information concerning the Winstart.bat file, see the following article in the Microsoft Knowledge Base:

134402 Some TSRs Moved from Autoexec.bat to Winstart.bat During Setup

The Win.ini File

The "load=" and "run=" lines in the [Windows] section of the file can start programs automatically. See the following section for more information.

The Startup Group

If the issue is resolved by bypassing the Startup group, remove each of the programs from the Startup group individually to isolate the problem program.

The Run Key in the Registry

WARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall Windows 95. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk.

NOTE: For information about how to edit the registry, view the Changing Keys And Values online Help topic in Registry Editor (Regedit.exe). Note that you should make a backup copy of the registry files (System.dat and User.dat) before you edit the registry.

You can prevent programs from loading by removing the program's string from the following registry key: 
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
Programs may also being loading from the following registry key: 
   HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run

Test Windows Configuration Files

To test the Windows configuration files, follow these steps:
  1. Boot to a command prompt.
  2. Rename the Win.ini file by typing the following line:

    ren c:\windows\win.ini *.bak

    Start Windows 95 by typing win. If this procedure corrects the problem, ensure that the "load=" and "run=" lines in the [Windows] section of the Win.ini file are either blank or preceded with a semicolon (;) to prevent the items from loading.
  3. Rename the System.ini file by typing the following line:

    ren c:\windows\system.ini *.bak

  4. Windows 95 requires a System.ini file to load the graphical user interface (GUI). Replace the original file by typing the following line:

    copy c:\windows\system.cb c:\windows\system.ini

    NOTE: Starting Windows 95 with the System.cb file does not load a driver for the mouse. Edit the new System.ini file, adding the following lines: 
          [386Enh]
      mouse=*vmouse, msmouse.vxd

      [boot]
      drivers=mmsystem.dll
      mouse.drv=mouse.drv
    Start Windows 95 by typing win at the command prompt. If replacing the original System.ini file with the System.cb file corrects the issue, the problem most likely resides with either the [boot] or [386Enh] sections of the original System.ini. Restore the original file to troubleshoot it.

    To isolate the cause of the problem, place a semicolon (;) at the beginning of a line to prevent the item from loading.
For more information about the System.ini file and its default entries, see the following article in the Microsoft Knowledge Base:

140441 Creating a New System.ini File Without Third-Party Drivers

PROTECTED-MODE DEVICE DRIVERS

Safe mode disables all protected-mode device drivers for Windows 95. Testing for incompatible components and resource conflicts can be conducted by disabling the protected-mode device drivers in Device Manager.

Removing Protected-Mode Device Drivers to Isolate Conflicts

  1. In Control Panel, double-click System.
  2. Click the Device Manager tab, and click the View Devices By Type option.
  3. Disable each of the protected-mode device drivers. For example:
    1. Double-click the Floppy Disk Controllers branch to expand it.
    2. Click Standard Floppy Disk Controller, and then click Properties.
    3. On the General tab, click the Original Configuration (Current) check box to clear it, and then click OK.

      NOTE: If you have enabled hardware profiles, there is a check box for each of the configurations. Clear the check box for the hardware profile you are troubleshooting.

      If there is no Original Configuration (Current) check box, click the Disable in This Hardware Profile check box to select it.

      NOTE: In Windows 95 OSR2, the user interface has changed. Click the Disable In This Hardware Profile check box to select it to disable a protected mode driver.
    4. Repeat steps A-C for each device in Device Manager.
  4. Click Close, and then restart the computer.
If the issue is resolved by disabling the protected-mode drivers in Device Manager, you may have a hardware conflict or a driver may be incompatible with your hardware. For more information about troubleshooting resource conflicts in Windows 95, see the following article in the Microsoft Knowledge Base:

133240 Troubleshooting Device Conflicts with Device Manager

If you determine that a Windows 95 protected-mode device driver is incompatible with your hardware, contact the hardware vendor to determine the availability of new drivers.

CHANGING THE VIDEO DRIVER TO STANDARD VGA DISPLAY DRIVER

NOTE: If you followed the directions in the previous section ("Removing Protected-Mode Drivers to Isolate Conflicts"), you changed the display driver to VGA, and you can skip to the next section. Disabling the display adapter sets your video to the VGA driver.

Safe mode starts Windows 95 with the VGA display driver. To determine if the issue you are experiencing is related to your video driver, change to the VGA driver for testing purposes.

NOTE: To ensure a safe return to your previous configuration:
  • Back up the System.ini file.
  • Note the current desktop area (resolution) and color palette.
  • Record the name of your current video adapter.
To change to the VGA display driver, follow these steps:
  1. Start Windows 95 in Safe mode.
  2. In Control Panel, double-click Display.
  3. On the Settings tab, click Change Display Type.
  4. In the Adapter Type area, click Change.
  5. Click the Show All Devices option.
  6. In the Manufacturers box, click (Standard Display Types). In the Models box, click Standard Display Adapter (VGA), and then click OK.
  7. Click OK or Close until you return to Control Panel. When you are prompted to restart your computer, do so.
If you determine that your video driver is incompatible with Windows 95, contact the hardware vendor to determine the availability of new drivers.

REGISTRY DAMAGE

When you start Windows 95 in Safe mode the registry is read minimally. Damage to the registry may not be evident when running in Safe mode; it may be necessary to replace the existing registry (System.dat) with a backup to determine if the issue is caused by a damaged registry. To troubleshoot a damaged registry, follow these steps:
  1. Boot to a command prompt.
  2. Type the following line to remove the file attributes from the backup of the registry:

    c:\windows\command\attrib -h -s -r c:\system.1st

  3. Remove the file attributes from the current registry by typing:

    c:\windows\command\attrib -h -s -r c:\windows\system.dat

  4. Rename the registry by typing:

    ren c:\windows\system.dat *.dax

  5. Copy the backup file to the current registry by typing:

    copy c:\system.1st c:\windows\system.dat

  6. Restart your computer.

    NOTE: The System.1st file is a backup of the registry created during the final stage of Windows 95 Setup. Therefore, the "Running Windows 95 for the first time" banner is displayed and Windows 95 finalizes settings as if it were being installed.
If replacing the System.dat file with the System.1st file resolves the issue, the problem may be related to registry damage. Programs and device drivers added after Windows 95 was installed may require reinstallation to update the new registry.

If the issue is not resolved, restore the original registry. To do so, follow these steps:
  1. Restart the computer to a command prompt.
  2. Type the following lines:

    c:\windows\command\attrib -s -h -r c:\windows\system.dat

    copy c:\windows\system.dax c:\windows\system.dat

  3. Restart the computer.
The Windows 95 CD-ROM includes tools for backing up your system files as well as the registry. For more information about these tools, see the following articles in the Microsoft Knowledge Base:

139437 Windows 95 Emergency Recovery Utility

135120 Configuration Backup Tool for Backing Up the Registry

IF THE PROBLEM PERSISTS

If the troubleshooting steps outlined in this article do not resolve the issue, the issue may be related to one or more of the following items:
  • Faulty hardware
  • The computer requires a special machine switch for HIMEM.SYS
  • CMOS settings may need to be changed (such as disabling shadow RAM)
  • The system ROM BIOS may require an upgrade to be compatible with Windows 95
  • A virus
  • An unsuccessful upgrade of a previous Windows installation
To determine if Windows 95 is compatible with your current system configuration it may be necessary to install Windows 95 to a clean directory.

If you have enough free disk space, install Windows 95 to an empty folder (such as a Win95 folder). For information about how to do so, see the following article in the Microsoft Knowledge Base:

142096 How to Reinstall Windows 95 to a New Folder

If this resolves the issue, your previous installation may have included components incompatible with Windows 95. Consult your computer's documentation or manufacturer for information about modifying the CMOS settings and the availability of BIOS upgrades.
Modification Type:MajorLast Reviewed:2/19/2002
Keywords:kbenv kbtshoot KB156126
©2002 Microsoft Corporation. All rights reserved.