an unhandled win32 exception occurred in w3wp.exe

Question

I get the following exception when trying to load an ASP.NET MVC website:

Unhandled exception at 0x07070a91 in w3wp.exe: 0xC0000005: Access violation reading location 0x00000000.

The Visual Studio Just-In-Time Debugger opens and the only information I can see in the debugger is this:

Call stack location:

msvbvm60.dll!06c00a91()

The website uses some COM objects and everything worked fine until last week. This problem appeared out of the blue.

This is the error log from Windows Event Viewer:

Faulting application name: w3wp.exe, version: 7.5.7601.17514, time stamp: 0x4ce7a5f8
Faulting module name: MSVBVM60.DLL, version: 6.0.98.15, time stamp: 0x4a5bda6c
Exception code: 0xc0000005
Fault offset: 0x00030a91
Faulting process id: 0x1a0
Faulting application start time: 0x01cd31fcb47f66d8
Faulting application path: C:\Windows\SysWOW64\inetsrv\w3wp.exe
Faulting module path: C:\Windows\system32\MSVBVM60.DLL
Report Id: f5db0ae3-9def-11e1-ad79-005056c00008

Do you have any suggestions to help troubleshoot this problem?

Edit: I managed to solve the problem and now everything works. The solution involved tweaking some registry settings that the custom dlls need in order to function properly. So the problem didn't actually appear out of the blue, I just didn't realize some registry values were modified, which caused a com dll to crash.

Solution 1

The information you provided above is not enough to provide a root cause however if you can provide more info about the exception you might get exact reason for this failure. You asked for suggestion to troubleshoot this problem so here they are:

You can use either any one of the 3 tools to troubleshoot this issue:

1. IIS Debug Diagnostics Tool v1.2

   Here is more info about how to use this tool: http://support.microsoft.com/kb/919790

2. DebugDiag

   Use the link below to understand how you can hook your w3wp process (it is user mode proces) with DebugDiag and collect more info about the crash:

   http://msdn.microsoft.com/en-us/library/ff420662.aspx

3. WinDBG

   Here is a link which will help you to load W3WP process in WinDBG and use some commands to extract more info about the crash:

   http://blog.whitesites.com/Debugging-Faulting-Application-w3wp-exe-Crashes__634424707278896484_blog.htm

Once you have more info about the exception, you can add above and will get prompt help.

Solution 2

Open the Advanced settings dialog of the Application pool that is serving the application in IIS Manager, and set: Enable 32-Bit Applications to True

Solution 3

Do the Following,

1) Give full rights to Temp & %temp% folders

2) Go to application pool properties & Change " Enable 32 bit application " to true

Solution 4

In my case, a program called "Web Companion" was installed.

After uninstalling it, the problem was fixed.

Solution 5

You may start by capturing a crash dump when this issue happens again,

http://support.microsoft.com/kb/2580960

Use Debug Diag 1.2 to set up a crash rule properly is step 1.

Once you have the dump, you can use WinDbg (part of Debugging Tools for Windows) to analyze it if you are familiar with dump analysis.

If you are not capable of analyzing that, my suggestion is that you open a support case via http://support.microsoft.com and share the dumps with Microsoft support engineers.

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