Problem with NuGet Microsoft Data SqlClient library

Question

Microsoft Data SqlClient is referenced in the Visual Studio C Sharp project. Code throws an error ' The type 'IDbColumnSchemaGenerator' is defined in an assembly that is not referenced. You must add a reference to assembly 'System.Data.Common, Version=4.2.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'. NuGet Microsoft.Data.SqlClient is showing as installed. have tried the following console commands

1.'dotnet nuget locals all --clear

2.'dotnet restore

3.'dotnet clean

4.'dotnet build - error 'build failed. But NuGet Microsoft Data SqlClient is reported as installed in NuGet Browse tab

Answer 1

assembly 'System.Data.Common' is a framework 4.* assembly. it can not be used with dotnet core. you must have a 4.* framework library reference in your project. you will need to replace it with a dotnet core compatible library.

Answer 2

You can try to follow the steps below to troubleshoot this problem.

1. Open up your solution in Visual Studio.
2. In Solution Explorer, right-click the References or Dependencies node, and then choose either Add Project Reference, Add Shared Project Reference, or Add COM Reference from the context menu.
3. Now the references window will open up - just select the correct DLL with your missing type and hit OK .

Answer 3

I have since tried to uninstall / re-install NuGet. Then new error returned -".....................\Microsoft.Data.SqlClient 6.1.2 failed to uninstall. Restart Visual Studio to finish the process." Consecutive restarts have not resolved issue - same error is repeated.

Have then carried out complete uninstall / re-install of Visual Studio 2022, same error is still being repeated

Screenshot 2025-10-10 105853.jpg

Answer 4

you can just delete the /obj & /bin folders to uninstall (if you get a file in use error, that's the same issue VS is having). then run:

dotnet restore

optionally you can edit the project file to remove the package reference.

but the Microsoft.Data.SqlClient package is unrelated to the System.Data.Common assembly reference error.

Answer 5

Have deleted the \bin and \obj folders for the project & restarted VS, and didn't get any locked file errors - deletes completed ok. But same error is still being shown " package .....................\Microsoft.Data.SqlClient 6.1.2 failed to uninstall. Restart VS to finish process"

Checked the project file, doesn't contain any reference to the SqlClient package.

If i could get the Microsoft.Data.SqlClient library added to the project i'd be happy, no intention of using the system.Data.Common package for the project.