It sounds like the Microsoft Visual C# 2012 script task has been removed or disabled in your installation of Visual Studio 2015. This could be due to an update or change in your Visual Studio installation.
To re-enable the Microsoft Visual C# 2012 script task, you can try the following steps:
- Close Visual Studio.
- Open the Visual Studio Installer from the Windows Start menu.
- Select the installation of Visual Studio that you are using.
- Click the Modify button.
- In the Modify screen, expand the Programming Languages node and select the option for C#.
- Check the box for "Integration Services Project support".
- Click the Modify button to apply the changes.
- This should add the Microsoft Visual C# 2012 script task back to the SSIS Toolbox in Visual Studio.
If these steps do not work, it is possible that the Microsoft Visual C# 2012 script task has been removed from your installation of Visual Studio. In that case, you may need to install an earlier version of Visual Studio or use a different tool to create the script task.