Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

dotnet build fails with multiple CopyToOutputDirectory tasks using same paths in different casing #4160

FrontPsych opened this issue Jan 12, 2020 · 0 comments


Copy link

@FrontPsych FrontPsych commented Jan 12, 2020


dotnet build fails on Linux distributions when a project has dependencies using CopyToOutputDirectory with same paths but in different casing.

Say we have a project with dependencies A and B. Each of those dependencies has set their image files to be copied to the output directory using:

  • Solution.sln
    • Dependency_A.csproj
      • Images/image_A.png
    • Dependency_B.csproj
      • images/image_B.png
    • Project.csproj
      • Dependencies/Projects
        • Dependency_A
        • Dependency_B

After running dotnet build, the build process manages to copy over only one dependency's image files but gets stuck trying to copy the other dependency's image files and eventually terminates in an error,

Actual outcome

The build fails.

Project.csproj build output directory:

  • ...
  • Images/image_A.png
  • ...

Error message

/usr/share/dotnet/sdk/3.1.100/Microsoft.Common.CurrentVersion.targets(4601,5): error MSB3027: Could not copy "/home/user/repos/folder/Dependency_B/images/image_B.png" to "bin/Debug/netcoreapp3.1/images/image_B.png". Exceeded retry count of 10. Failed.  [/home/user/repos/folder/Project/Project.csproj]
/usr/share/dotnet/sdk/3.1.100/Microsoft.Common.CurrentVersion.targets(4601,5): error MSB3021: Unable to copy file "/home/user/repos/folder/Dependency_B/images/image_B.png" to "bin/Debug/netcoreapp3.1/images/image_B.png". Could not find a part of the path 'home/user/repos/folder/Project/bin/Debug/netcoreapp3.1/images/image_B.png'. [/home/user/repos/folder/Project/Project.csproj]

Desired outcome

Build succeeds.

Project.csproj build output directory:

  • ...
  • Images/image_A.png
  • images/image_B.png
  • ...


  • Linux distribution: Ubuntu 19.10
  • .NET Core SDK: 3.1
  • ASP.NET Core runtime: 3.1
  • .NET Core runtime: 3.1

Reproduce steps


  • Use a Linux distribution.
  • Have .NET Core 3.1 installed.


  1. Clone the repository
    git clone
  2. Navigate to the root folder IssueReport/.
  3. Build the solution.
    dotnet build IssueReport.sln
  4. Done, the build will finish with 10 warnings and 2 errors.

Interesting caveats

  • The build can sometimes(1/20) be successful on the first try. In order to reproduce the error clear the build output directory and retry.
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
None yet
1 participant
You can’t perform that action at this time.