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How do I research this error RRS feed

  • Question

  • Occasionally (2-3 times a week) we receive this error message on a build - we have 14 different build definitions, it can be any one of them.  No pattern.  The answer is to kick off a new build and it always succeeds the 2nd time.  Has anyone seen this before?

    "C:\Builds\5\Breeze\Tip_xxxxx\src\SharedProjects\Business\xxxxx.xxxxxxx.csproj" (default target) (15) ->
    (MarkupCompilePass2 target) -> 
      C:\Windows\Microsoft.NET\Framework64\v4.0.30319\Microsoft.WinFx.targets(343,9): error MC2000: Unknown build error, 'Duplicate type with name '' in assembly 'xxxx.xxxxx, Version=x.xxx.6270.33090, Culture=neutral, PublicKeyToken=null'.'  [C:\Builds\5\xxxx\Tip_xxxxx\src\SharedProjects\Business\xxxx.xxxx.csproj]

    Thanks in advance,

    John

    Friday, March 3, 2017 12:00 PM

All replies

  • Hi John Hennesey,

    I'm currently not sure on which condition this issue occurs. On my computer, I tried creating 2 classes with the same name but different namespace in a class library, adding 2 test methods for them in the same test project. But not get the same error as yours. I would like give you some suggestions to you:
    1. Do you get this error message when build the solution in Visual Studio?
    2. Have you try to MSBuild.exe from “C:\Program Files (x86)\MSBuild\14.0\Bin\ MSBuild.exe” instead of “C:\Windows\Microsoft.NET\Framework64\v4.0.30319\MSBuild.exe”?
    3. Check assembly 'xxxx.xxxxx, Could you find that multiple class in the assembly 'xxxx.xxxxx?


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    Monday, March 6, 2017 6:38 AM
  • It builds just fine on our local VS for every developer.  99% of the time it builds properly on our dedicated build machine.  It is just every now and then it fails.

    We have always attributed it to a network issue, but when the network guys looked into it they reported no network outages/problems during the build time.  The solution to 'fixing' it is to kick off a new build which almost always succeeds.

    Is there any place where the MC200 error details are logged?  I didn't see anything in the event viewer.  Might there be an MSBuild log deep somewhere in the filesystem that would track the details?

    Thanks,
    John

    Monday, March 6, 2017 1:32 PM
  • Hi John Hennesey,

    Thank you for your reply.
    Log file from Visual Studio is only supported for C++ projects. we just have to work with the output window for others. But we can change the amount of information included in the build log.
    1. On the menu bar, choose Tools, Options.
    2. On the Projects and Solutions page, choose the Build and Run page.
    3. In the MSBuild project build output verbosity list, choose one of the (Detailed/Diagnostic) values, and then choose the OK button.
    You can refer to the https://msdn.microsoft.com/en-us/library/jj651643.aspx for detail.
    Besides, If you use MSBuild command line build the project, You can use the /fileLogger (fl) switch to save build data to a file.


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    Tuesday, March 7, 2017 5:25 AM
  • Thank you - would the /fileLogger argument provide more detail than what is in the build log provided in the web site?  I am really after the details of the MC200 Unknown Build Error.
    Tuesday, March 7, 2017 8:51 PM
  • Hi John Hennesey,

    The /fileLogger argument is used to collect the MSBuild log. Does the MC200 Unknown Build Error occurred in the web site? If yes, What kind of build do you use, TFS Build or other build method?


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    Wednesday, March 8, 2017 11:38 AM