What to do about an Illegal operation message when using Internet Explorer

[Unregistered]

I have a client who has a Windows 98 PC and fixed the problem by doing the following: 1. Search all files with the name MSVCRT.DLL. 2. The file that is corrupted is in the Windows\System directory so it cannot be deleted from Windows. 3. Look for another file with the same name but is newer. Lets say this file in c:\xxx\yyy 4. Restart PC in DOS mode. 5. CD to windows\system 6. Rename MSVCRT.DLL to MSVCRT.DL_ 7. Copy c:\xxx\yyy\MSVCRT.DLL to c:\windows\system 8. Reboot and you will not encounter this problem again.

[Unregistered]

Iexplore caused an invalid page fault in msvcrt.dll

Perhaps this will help:

<Program> Causes Invalid Page Fault Error in Msvcrt.dll (Q192123)
http://support.microsoft.com/default.aspx?scid.....kb;EN-US;Q192123

Also make sure you do not have more than one copy of msvcrt.dll installed on your system - rename any *not* in c:\windows\system.

Check that the version you have installed is correct as per this link. It is possible another programme has replaced the correct version of the DLL with a bad copy or incorrect version.

http://support.microsoft.com/servicedesks/fileversion/dllinfo.asp?

It has been reported that replacing msvcrt.dll using System File Checker/MSCONFIG has fixed the problem for some users.

Yahoo Companion is known to cause this error sometimes. Instructions on uninstalling here:

How to Uninstall or Turn off the Yahoo! Companion Browser Toolbar (Q303047)
http://support.microsoft.com/default.aspx?scid.....kb;EN-US;Q303047

Update: 7 June 2004
There has been a noticeable increase in error message involving msvcrt.dll in the newsgroups; sudden increases like this are *always* traced to a new malware release, or another common programme stuffing up people's systems. If the above advice doesn't help you with your problem, check out my troubleshooting advice specific to malware.