msdia80.dll in Vista x64 OS in Windows Vista Posted October 14, 2008 Hi Guys.I already found one explaination from Microsoft. But I still don't think it explained my all problem.http://support.microsoft.com/kb/927665/en-usAccording to this artical, The msdia80.dll should be under:driver： \Program Files\Common Files\Microsoft Shared\VC\msdia80.dll In my machine, I have 2 partition.In fact, in x64 OS, I can find 2 files.1st one is under the D:\The other one is in driver： \Program Files(x86)\Common Files\Microsoft Shared\VC\msdia80.dllSo, according to MS site. I should also put the D:\msdia80.dll into this folder.driver： \Program Files\Common Files\Microsoft Shared\VC\msdia80.dll.My question is:Is this 2 gonna conflict with eachother? Or I should keep them both?driver： \Program Files\Common Files\Microsoft Shared\VC\msdia80.dll driver： \Program Files(x86)\Common Files\Microsoft Shared\VC\msdia80.dll Anyone could answer my problem? Please give me some hint!Thanks!