I'm using windbg (the latest available from the MSDN download page). I'm trying to debug a deadlock in my app, and !locks would be very useful. However, it's not working: 0:023> !locks NTSDEXTS: Unable to resolve ntdll!RTL_CRITICAL_SECTION_DEBUG type NTSDEXTS: Please check your symbols I don't know why it's upset. I've got symbols properly loaded: 0:023> .sympath Symbol search path is: srv* Expanded Symbol search path is: cache*c:\debuggers\sym;SRV*http://msdl.microsoft.com/download/symbols And NTSD agrees: 0:023> lmv m ntdll start end module name 777b0000 77930000 ntdll (pdb symbols) c:\debuggers\sym\wntdll.pdb\E9D10FA3EB884A23A5854E04FB7E2F0C2\wntdll.pdb Loaded symbol image file: C:\Windows\SysWOW64\ntdll.dll Image path: ntdll.dll Image name: ntdll.dll Timestamp: Mon Jul 13 18:11:23 2009 (4A5BDB3B) CheckSum: 00148A78 ImageSize: 00180000 File version: 6.1.7600.16385 Product version: 6.1.7600.16385 File flags: 0 (Mask 3F) File OS: 40004 NT Win32 File type: 2.0 Dll File date: 00000000.00000000 Translations: 0409.04b0 CompanyName: Microsoft Corporation ProductName: Microsoft® Windows® Operating System InternalName: ntdll.dll OriginalFilename: ntdll.dll ProductVersion: 6.1.7600.16385 FileVersion: 6.1.7600.16385 (win7_rtm.090713-1255) FileDescription: NT Layer DLL LegalCopyright: © Microsoft Corporation. All rights reserved. And the stack looks good: 0:036> k ChildEBP RetAddr 1506fdd8 7784f546 ntdll!DbgBreakPoint 1506fe08 75bf3677 ntdll!DbgUiRemoteBreakin+0x3c 1506fe14 777e9d72 kernel32!BaseThreadInitThunk+0xe 1506fe54 777e9d45 ntdll!__RtlUserThreadStart+0x70 1506fe6c 00000000 ntdll!_RtlUserThreadStart+0x1b Any help is appreciated.