I've got a program that I'm trying to debug but when I attach WinDbg to the process and look at the call stack for the thread that I'm interested in I sometimes see that the 'this' pointer is NULL, or that some of the member data in my class is NULL... after a lot of investigation I concoluded that this cannot be possible, so I got my code to print out the value of the 'this' pointer once a second. Sure enough the printed 'this' pointer is perfectly valid yet WinDbg still says its NULL.

Any idea why WinDbg could be getting it wrong?

The PDB file definitely matches the EXE (i.e. I don't have an old PDB against a nwer version of the EXE).

Also, I'm using the old RaiseException trick to name my threads in the debugger, yet sometimes I only see some of my threads with names in WinDbg even though I know I named them all. Sometimes none of them have names. Could this be because I'm naming my threads before attaching WinDbg to the process? i.e. does the debugger have to be running at the time I call RaiseException?

Thanks for your help
Ben