Nearly every Windows user has at one time or another seen one of the errors mentioned in the title of this document. If you've seen any of these errors appear only on rare occasion, and without any consistency, it's probably not worth troubleshooting. There can be many causes of the above errors or problems with your computer freezing up, and the process of troubleshooting can involve quite a bit of time attempting to hunt down the problem. If you're experiencing recurrent or duplicable errors of this sort, this document explains the origins of these errors and what you can do to resolve them.

Both General Protection Faults (GPFs) and Illegal Operations are the same thing. The term GPF is used in Windows 3.x, whereas Illegal Operations are used in Windows 95/98. The official Microsoft explanation of this type of error is:

"As the name implies, this fault means something was attempted that is not allowed because it would violate the protection features built into the CPU. [...] A typical cause of this invalid fault is executing garbage, but unlike the invalid opcode, the instruction is legal; however, the particular form of the instruction is illegal at the time."

In translation, the software you were using sent the computer a command that didn't make sense. In our experience, this problem is most commonly caused by data corruption or by a conflict between two programs that are accessing the processor simultaneously.

"A page fault occurs when an access is made to memory that is not currently mapped, (not currently available). [Also, an application can] make the memory unavailable by using the paging features of the CPU so that any [other] application that tries to read or write to this memory will be stopped by an invalid page fault."

In translation, an Invalid Page Fault occurs when one program running on your computer tries to access memory that another program has already claimed as its' own.

Typically, system freeze-ups are caused by the same things as GPFs, Illegal Operations and Invalid Page Faults... but create a state in which the processor can no longer respond to system requests, and an error message cannot be displayed.

GPFs, Illegal Operations and Invalid Page Faults can occur on any computer running any sort of software. They're -not- specifically Internet or CoreComm related, and are almost always related to either file corruption (the file is incomplete or missing information on your hard drive) or conflicts with another piece of software that is running on your computer. Unfortunately, due to the complex interactions between various software packages, GPFs, Illegal Operation and Invalid Page Fault errors sometimes cannot be eliminated, but there almost always is a work-around. This document outlines the various things you can do to minimize these errors.

The first thing to do when you get an error of this sort is to note two things:

1. What module or program did the error occur in?

   In the GPF dialogs box, it will show the filename that the GPF occurred in. This is the file which contains the function that caused the conflict that generated the GPF. If you get an Illegal Operation or Invalid Page Fault, you can check the name of the program which generated the error by clicking on the DETAILS>> button. For example, "NETSCAPE.EXE performed an illegal operation..." would point to your Netscape software as a culprit.

2. What were you doing at the time the error occurred?

Sometimes, these types of errors don't give a filename that is useful for troubleshooting... but any consistency in the situations during which the error occurred may be valuable for troubleshooting.

Once you've obtained this information, see if any of the situations below match what you're experiencing.

Invalid Page Fault errors in your mail program can be caused by a corrupt inbox file. This most commonly happens in Netscape Navigator or Netscape Communicator. To resolve this problem, follow these steps:

Close Netscape Navigator or Communicator. Using Windows 95/98 Explorer (found in Start -> Programs -> Explorer) or the Windows 3.1 File Manager, locate the files named INBOX and INBOX.SNM. In Windows95/98, these are most commonly in the \Program Files\Netscape\Navigator\Mail or \Program Files\Netscape\User\username\Mail directories, whereas in Windows 3.1, they are most commonly in \NETSCAPE\MAIL, or \NETSCAPE\USER\USERNAME\MAIL.

Rename the files to OLDINBOX and OLDINBOX.SNM. The next time you load Netscape and enter the mail portion of the program, these files will be recreated and the error will disappear. If you wish to see your old mail, you can edit the OLDINBOX and OLDINBOX.SNM files with a text editor like WordPad, Microsoft Word, UltraEdit, etc.

Note: If you are getting similar errors when attempting to send mail, follow the same steps using OUTBOX and OUTBOX.SNM file names.

If you are having this problem with a different mail program, the procedure is basically the same. Locate the mail program's inbox files and rename them. They may have a different file extension than .snm, but you can usually do a search for inbox and inbox.* and you should be able to find them. Rename them to oldinbox and oldinbox.(extension). You will also be able to then access these files using a text editor, and the program should not crash anymore when receiving new mail.

If you are getting several invalid page faults in kernel32 and are running Windows 95, you may benefit from the Microsoft "Kernel32" Update.

Earlier versions of Windows 95 experienced a problem where, if you were running Internet applications for an extended period of time, the system resources were gradually depleted, resulting an a Invalid Page Fault when all of the system memory was in use.

The fix is available at the Microsoft Support Center.

Often, this error message occurs when running Quarterdeck's CleanSweep software. Contact Quarterdeck's support department for a update, or visit their web page.

This error is caused when you install the Windows Dial-up Networking software from a version of the Windows installation files that is different than the version of Windows that is on your computer. The solution is to uninstall Dial-up Networking from your computer, obtain a set of Windows installation files that are the same version as what you already have installed, and to reinstall Dial-up Networking from those files (contact your computer's manufacturer if you need replacement files).

Errors of this sort were unfortunately common in Internet Explorer 2.0, which was distributed with many systems. These problems have been generally fixed in the more recent versions of Internet Explorer, which is available for download from http://www.Microsoft.com/windows/ie/download/

Errors of this sort can be caused by a number of factors.

To eliminate the possibility of data corruption, you should uninstall and reload your Netscape software. To avoid losing any information you may have previously saved in Netscape, we recommend backing up your old Netscape directories (\Program Files\Netscape in Windows 95/98, \NETSCAPE in Windows 3.1) by copying it to a different directory name before uninstalling.

If you are going to be reinstalling Netscape anyway, you should consider upgrading to the most recent version. You can download the latest version from their web site at http://Netscape.com/download/ or from their FTP site at ftp.netscape.com (anonymous login).

Before you uninstall Netscape, back sure you have a Netscape installation disc, disks, or file. To uninstall in Windows 95/98, go into Start -> Settings -> Control Panels -> Add/Remove Programs, click on the listing for Netscape, and click on Remove. In Windows 3.1, you can double-click on the icon for the Uninstaller in your Netscape program group. After uninstalling the software, re-load it off of your disks, CD, or from the file you downloaded.

The next step is to look into your system configuration to make sure it matches or exceeds Netscape's recommended settings. If you feel very uncomfortable modifying system files, you may want to have a computer professional look at your system instead of modifying it yourself.

In Windows 3.1, select File -> Run in the Program Manager, type in SysEdit and hit enter. In Windows 95/98, select Start -> Run, type in SysEdit and hit enter. On both systems, you'll see the System Configuration Editor appear on the screen.

Click on the window labeled CONFIG.SYS. If there is a line that starts FILES=, and the amount is less than 99, change the amount to 99. If the FILES= line does not exist, add the line FILES=99 below the last line. If there is a line that starts with BUFFERS=, and you're using Windows 3.1, make sure that the line reads BUFFERS=10,0 (an exception: if you're aware that you're not running either Smartdrive or that you're not using 32-bit disk access, make it BUFFERS=40,0. If you're not certain, leave it alone). STACKS= should read STACKS=9,256 (if this line does not exist, add it below the last line). The line which begins FCBS= should be 4,0 or higher (if FCSB= does not exist, add FCBS=4,0 to the last line of the file).

When you're finished with the above, click on the window labeled AUTOEXEC.BAT. There should be a line that reads SET TEMP=C:\TEMP . If this line does not exist, or if TEMP is set to something other than C:\TEMP , add it as the first line of the file. After we make a few more changes and exit the System Configuration Editor, go into File Manager and create the TEMP directory under the root of the C: drive by clicking on the File menu and selecting "New Directory" or "New> Folder".

Next, click on the window labeled SYSTEM.INI. Check to make sure the following lines are in accordance with these suggestions:

LOAD= and RUN=
These can cause programs to start and run invisibly at the beginning of a Windows session. You can prevent non-essential programs from being launched by these lines by placing a semi-colon ( ; ) at the beginning of the line.

SHELL=
Make sure SHELL=PROGMAN, PROGMAN.EXE or EXPLORER.EXE. The Netscape Corporation does not support the installation of Netscape under third-party shells like Norton Desktop or Tabworks. Uninstall that software if an uninstall utility is available, or place a semi-colon ( ; ) at the beginning of the line.

COMM.DRV=
Should equal COMM.DRV unless wrpi.drv is specified, or you are using a PCMCIA card on a Windows 3.1 system.

VCD:
Search the SYSTEM.INI file for VCD. The only line that should have VCD is DEVICE=*VCD unless they're using a PCMCIA modem. Place a semi-colon ( ; ) at the beginning of any other lines containing VCD.

VNT:
Search the SYSTEM.INI for VNT. The only line with VNT should be: DEVICE=C:\NETSCAPE\SYSTEM\VNTSTIMD.EXE or whatever the path is to your Netscape directory. Any other lines with this should get a semi-colon ( ; ) placed at the beginning.

Click on File -> Save, then File -> Exit, and you're finished with the System Configuration Editor.

If you're using Windows 3.1, you should check to make sure your swap file is set correctly. Go into Control Panel -> 386 Enhanced -> Virtual Memory, and make sure that the swapfile is set to be Permanent. The amount of space in the swapfile should be equal to the recommended size.

After making these changes, reboot your system and see if the problems continue. If they do, see the section on general troubleshooting below.

As stated previously, a common reason for error messages of this type is a conflict between two or more programs running on your machine. The program listed in the GPF, Illegal Operation or Page Fault error message may clue you in to what program is causing the problem by the way the filename looks. Open up the task list (Press [CTRL][ESC] in Windows 3.1 or [CTRL][ALT][DEL] in Windows 95/98), close the program that the error is occurring in by selecting the program and clicking on End Task to see if your Internet software runs reliably. If so, try visiting the web site of that software's developer to see if they have a fix or work-around for your particular conflict. If you do not know which program is linked with the file that is causing the problem, you may want to simply close all unnecessary programs that are running to see if your software functions more reliably.

The problems you're experiencing may be linked with the video drivers that you are using. To check this, you'll want to (at least temporarily) change the video mode in Windows to VGA.

• In Windows 95/98, Click on your Start button, go to Settings and Control Panel. Double click the Display icon and select the Settings tab. Set the Colors to 256 and the Desktop area to 640x480 and then click on OK.
• In Windows 3.1, go into the Main program group, select Windows Setup, go to the Settings menu and select Change Options or Change System Options, then move the Display setting to read simply VGA.

After making these changes, you'll probably need to restart Windows. If this resolves the problem, you'll want to check with your computer/video card manufacturer to see if updated video drivers are available which may resolve this problem.

Lastly, check for multiple WinSock files. Search for WINSOCK.DLL files in Windows 3.1 by going into the File Manager, click on the File menu, select Search, and search for WINSOCK.DLL starting in C:\. Rename (File -> Rename) any winsock.dll file to winsock.bak if it is -not- in a \NETSCAPE or dialer directory. In Windows 95/98, you can do this by selecting Start -> Find -> Files or Folders, searching for WinSock.dll, and renaming any winsock.dll files that are -not- found in the \WINDOWS directory. In Windows 95/98 there is also a WSock32.dll file you will need to search for. Rename any wsock32.dll files that are -not- found in \WINDOWS\SYSTEM directory.

If you continue to experience problems after this troubleshooting, you have three more options:

1. Check the web site of the manufacturer to search to see if they have a resolution to the exact error you're getting on their web site.
   Netscape
   Microsoft
2. Try a different browser. If you're still having problems in Netscape, try Internet Explorer, and vice versa.
   Internet Explorer
   Netscape Navigator/Communicator
3. If problems with Illegal Operation errors, GPFs, Invalid Page Faults, rebooting or freeze-ups continue even with another browser and after checking to make sure -only- the necessary software is running, have your computer analyzed by a professional service center. These errors not only stem from software (which they'll be able to check directly), but also from problems with your computer's hardware (the physical components of your computer may be corrupt or broken).