define a value for metadata "CopyLocal"???

Hi@Wally96333.Welcome Microsoft Q&A.

The error message you're encountering typically indicates a problem with the project's references or the build configuration. The "CopyLocal" metadata is used to determine whether a referenced assembly should be copied to the output directory when building the project. Here's how you can troubleshoot and resolve this issue:

Check Reference Properties:

Open your project in Visual Studio.

Go to the "References" node in the Solution Explorer.

Find the reference to "BouncyCastle.Crypto.dll."

Right-click on the reference and select "Properties."

Make sure the "Copy Local" property is set to "True."

Check Project Configuration:

Ensure that the project configuration for "Release" mode is correctly set up.

Right-click on the project in Solution Explorer and select "Properties."

Navigate to the "Build" tab on the left.

Check the "Configuration" dropdown to ensure you are configuring the "Release" mode.

Look for any unusual settings that might be causing the issue.

Clean and Rebuild:

Sometimes, build issues can be resolved by cleaning and rebuilding the project.

Right-click on the project in Solution Explorer and select "Clean."

After the clean operation completes, right-click again and select "Rebuild."

Ensure that there are no build errors in the "Error List" window.

NuGet Package Restore:

If you are using NuGet packages, ensure that package restore is enabled and working correctly.

Right-click on the solution in Solution Explorer and select "Restore NuGet Packages."

Check for Package Conflicts:

It's possible that there's a conflict between different versions of the BouncyCastle library.

Make sure that all packages in your project are using compatible versions.

Use NuGet Package Manager to update or downgrade packages as needed to resolve conflicts.

Check the .csproj File:

Open the .csproj file of your project in a text editor.

Manually inspect the references section to ensure that there are no unusual or conflicting references.

Look for any references to "BouncyCastle.Crypto.dll" and check if the "Copy Local" property is specified.

If you still have questions, please feel free to let me know.

Thank you for the reply.

Make sure the "Copy Local" property is set to "True."

"Copy Local" is set to "False". This could very well be my problem.

When I try to set it to "True", VS2017 sets it back to "False" when I click off of it.

VS2017 will not accept my change.

I tried to run Nuget Restore. There is nothing to restore.

VVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVV

All packages are already installed and there is nothing to restore.

Time Elapsed: 00:00:00.2523003

========== Finished ==========

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

I changed the BouncyCastle version in NuGet Package Manager.

I can no longer find it in my .csproj file: It was removed. (It was there before.)

When I right-click on "BouncyCastle" and open "properties" there is nothing in the Properties window.

I see that MailKit is using BouncyCastle.Cryptography. I updated MailKit, along with BouncyCastle.Cryptography.

The error is as follows:

The item "C:\ ... \X_Solution\packages\BouncyCastle.Cryptography.2.2.1\lib\net461\BouncyCastle.Cryptography.dll" in item list "ReferencePath" does not define a value for metadata "CopyLocal". In order to use this metadata, either qualify it by specifying %(ReferencePath.CopyLocal), or ensure that all items in this list define a value for this metadata. Primary_Calc_Console_01

When I look at properties for BouncyCastle.Cryptography, I see that "Copy Local" is set to "True".

HOWEVER, the reference to "BouncyCastle.Cryptography" has been reintroduced to the .csproj file.

  <ItemGroup>
    <Reference Include="BouncyCastle.Cryptography, Version=2.0.0.0, Culture=neutral, PublicKeyToken=072edcf4a5328938, processorArchitecture=MSIL">
      <HintPath>packages\BouncyCastle.Cryptography.2.2.1\lib\net461\BouncyCastle.Cryptography.dll</HintPath>
    </Reference>