I can’t debug a Windows 7 dump under Vista. Or, can I?

Yes I can. (With the help of Volker von Einem and Doug Stewart.)

This particular issue is caused by different versions of the .NET Framework for Windows 7 and Vista:

4927 on Windows 7, 4200 on Vista SP2: http://blogs.msdn.com/b/dougste/archive/2007/09/06/version-history-of-the-clr-2-0.aspx


This means, there is an error when using SOS commands in WinDbg, like Volker encountered it three years ago: http://voneinem-windbg.blogspot.com/2007/10/failed-to-load-data-access-dll.html

CLRDLL: C:windowsMicrosoft.NETFrameworkv2.0.50727mscordacwks.dll:2.0.50727.4200 f:0
doesn’t match desired version 2.0.50727.4927 f:0
CLRDLL: Unable to find mscordacwks_x86_x86_2.0.50727.4927.dll by mscorwks search
CLRDLL: Unable to find ‘mscordacwks_x86_x86_2.0.50727.4927.dll’ on the path
CLRDLL: Unable to get version info for ‘C:Tempv2.0.50727.4297mscordacwks_x86_x86_2.0.50727.4927.dll’, Win32 error 0n87
CLRDLL: ERROR: Unable to load DLL mscordacwks_x86_x86_2.0.50727.4927.dll, Win32 error 0n87
Failed to load data access DLL, 0x80004005


The fix is:

  1. Make sure to use the Microsoft symbol server, i.e. set the symbol path like srv*C:TempSymbols*http://msdl.microsoft.com/download/symbols;cache*C:TempSymbols
  2. Get the file mscordacwks.dll from the Windows 7 machine.
  3. Rename it to mscordacwks_x86_x86_2.0.50727.4927.dll.
  4. Set the exepath of WinDbg so it can find it.
  5. Rinse the managed debugger.

.exepath+ C:Tempv2.0.50727.4297

.cordll -ve -u –l


More information is available from Doug Stewart: http://blogs.msdn.com/b/dougste/archive/2009/02/18/failed-to-load-data-access-dll-0x80004005-or-what-is-mscordacwks-dll.aspx

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1 Response to I can’t debug a Windows 7 dump under Vista. Or, can I?

  1. Henry says:

    MS10-060 changes the game to 2.0.50727.4206 (Vista SP2) vs. 2.0.50727.4952 (Windows 7).The advice remains, copy mscordacwks.dll as mscordacwks_x86_x86_2.0.50727.4952.dll and make sure its in the executable path or the symbol directory for mscorwks.pdb.

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