One reason for "unknown software exception 0xc0020001 occured in the application at location 0x7c812afb"

I've been obsessed with this exception for several days. Finally, I found the reason. Hope it can help you.

Problem

I created an ActiveX project which communicates with several different hardware. After debugging, when I close IE7, the exception above pops up with no more information. The exception dialog appears after the main form Dispose() fun.

protected override void Dispose(bool disposing)
{
    //...close several services
    if (disposing && (components != null))
    {
        components.Dispose();
    }
    base.Dispose(disposing);  //after this sentence          
}

There many suggestions for this exception on the web, however they don't give me effective help.

Solved

Occasionally, I change the debug browser to a different one which still uses the IE7 kernel. When closing the debug browser window at this time, the output window of VS2008 gives out the exception code, 0x00000005. Memory access problem! I try to load the hardware DLL one by one, and find one device's DLL release the devil.

Conclusion

1. This exception is caused by unmanaged code from hardware provider.
2. Trying another debug tool may give you a surprise.