Final answer:
To open an SSIS package in Visual Studio 2019, first ensure that SQL Server Data Tools and the SQL Server Integration Services Projects extension are installed. Then, use the Open Project/Solution option to navigate to and load the .dtproj file into the Solution Explorer.
Step-by-step explanation:
To open an SSIS package in Visual Studio 2019, you must have the right tools installed. Make sure you have both the SQL Server Data Tools (SSDT) and the appropriate version of the SQL Server Integration Services Projects extension for Visual Studio 2019. Here is a step-by-step guide: Open Visual Studio 2019. Go to Extensions > Manage Extensions. Search for the 'SQL Server Integration Services Projects' extension and install it.
Once the extension is installed, restart Visual Studio. Select File > Open > Project/Solution, or press Ctrl+Shift+O. Navigate to the .dt proj file that represents the SSIS package and select it. Click 'Open' to load the SSIS package into the Solution Explorer. If you're opening an SSIS package that was created in an earlier version of Visual Studio, you may be prompted to upgrade the project. Always make sure to backup your SSIS packages before performing an upgrade.