Why is Visual Studio 2015 adding stdole.dll and Microsoft.AnalysisServices.AdomdClient.dll to my project?

Question

These DLLs are not added to my project in prior versions of Visual Studio. My guess is that one of my references has a dependency to these DLLs. From what I've read, the highlighted Microsoft.Office.Interop.Excel might be the one. Can anyone confirm this? I should also note that VS 2015 always publishes these DLLs as well even if I exclude them from the the project. If I delete them, VS 2015 will remake them.

Edit: I have confirmed that the Excel and Office references are what's causing the inclusion of stdole.dll. See selected answer below to remove stdole.dll.

I've crossed out the custom references. Let me know if more information is needed. Here's my current references:

Answer 1

As others indicated, stdole.dll is a Primary Interop Assembly for a bunch of Office COM interop components. You can determine why it's getting included in your project by doing the following.

In Visual Studio, go to Tools > Options > Projects and Solutions > Build and Run. Change the "MSBuild project build output verbosity" setting to Detailed. Now clean and rebuild your project.

Open the Output window and search for stdole. You should find a section like this:

25>  Dependency "stdole, Version=7.0.3300.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a". 25>      Resolved file path is "D:\Program Files (x86)\Microsoft Visual Studio 12.0\Visual Studio Tools for Office\PIA\Common\stdole.dll". 25>      Reference found at search path location "{Registry:Software\Microsoft\.NETFramework,v4.0,AssemblyFoldersEx}". 25>          For SearchPath "D:\Git\FoobarServices\Dependencies\Dependencies". 25>          Considered "D:\Git\FoobarServices\Dependencies\stdole.winmd", but it didn't exist. 25>          Considered "D:\Git\FoobarServices\Dependencies\stdole.dll", but it didn't exist. 25>          Considered "D:\Git\FoobarServices\Dependencies\stdole.exe", but it didn't exist. 25>          For SearchPath "{CandidateAssemblyFiles}". 25>          Considered "Dependencies\CrystalDecisions.CrystalReports.Engine.dll", but its name "CrystalDecisions.CrystalReports.Engine" didn't match. 25>          Considered "Dependencies\CrystalDecisions.Enterprise.Framework.dll", but its name "CrystalDecisions.Enterprise.Framework" didn't match. 25>          Considered "Dependencies\CrystalDecisions.Enterprise.InfoStore.dll", but its name "CrystalDecisions.Enterprise.InfoStore" didn't match. 25>          Considered "Dependencies\CrystalDecisions.ReportSource.dll", but its name "CrystalDecisions.ReportSource" didn't match. 25>          Considered "Dependencies\CrystalDecisions.Shared.dll", but its name "CrystalDecisions.Shared" didn't match. 25>          Considered "Dependencies\CrystalDecisions.Web.dll", but its name "CrystalDecisions.Web" didn't match. 25>          For SearchPath "{TargetFrameworkDirectory}". 25>          Considered "C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.0\stdole.winmd", but it didn't exist. 25>          Considered "C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.0\stdole.dll", but it didn't exist. 25>          Considered "C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.0\stdole.exe", but it didn't exist. 25>          For SearchPath "{Registry:Software\Microsoft\.NETFramework,v4.0,AssemblyFoldersEx}". 25>          Considered AssemblyFoldersEx locations. 25>      Required by "CrystalDecisions.Web, Version=11.5.3700.0, Culture=neutral, PublicKeyToken=692fbea5521e1304, processorArchitecture=MSIL". 25>      Required by "CrystalDecisions.ReportSource, Version=11.5.3700.0, Culture=neutral, PublicKeyToken=692fbea5521e1304, processorArchitecture=MSIL". 25>      Required by "CrystalDecisions.CrystalReports.Engine, Version=11.5.3700.0, Culture=neutral, PublicKeyToken=692fbea5521e1304, processorArchitecture=MSIL". 25>      Required by "CrystalDecisions.Enterprise.InfoStore, Version=11.5.3300.0, Culture=neutral, PublicKeyToken=692fbea5521e1304". 25>      The ImageRuntimeVersion for this reference is "v1.0.3705". 

You can see where Visual Studio searched for the assembly as well what requires it at the bottom. In my case it's a bunch of old Crystal Reports assemblies.

Sometimes you can embed the interop types via the dependencies as Tony suggests, but not always. For me, the Crystal Reports assemblies do not support this.

I fixed this problem (and the insidious one scottsanpedro mentioned) by copying the stdole.dll (32KB, digitally signed) from C:\Program Files (x86)\Microsoft.NET\Primary Interop Assemblies\ into a "Dependencies" folder inside my project. I added the file to my project and added an explicit reference to it (Add Reference > Browse). Finally I opened the new reference's properties and set Embed Interop Types to True.

This seems to be a better situation. I shouldn't need to worry about getting an unsigned version of the assembly.