Installing Visual Studio Versions Side-by-Side
You can install this version of Visual Studio on a computer that already has an earlier version installed. If you encounter an installation failure, you can use the log collection tool to collect information about the failures so you can debug the issues yourself.
We recommend that you install Visual Studio versions in the order in which they were released. For example, install Visual Studio 2010 before you install Visual Studio 2012. Review the Readme file on the Microsoft website for more detailed installation instructions.
Before you install versions side by side, review the following conditions:
If you open in Visual Studio 2012 a solution from Visual Studio 2010 with Service Pack 1 (SP1), you can later open and modify the solution again in Visual Studio 2010 SP1 as long as you have not implemented any Visual Studio 2012-only features, such as targeting the .NET Framework 4.5.
If you try to open in Visual Studio 2012 a solution from a version that is earlier than Visual Studio 2010 SP1, including Visual Studio 2010, you might need to modify your projects and files to be compatible with Visual Studio 2012. For more information about project types and backward compatibility, see Visual Studio 2012 Compatibility and, on the Microsoft website, Visual Studio Project Converter.
If you uninstall a version of Visual Studio on a computer that has more than one version installed, the file associations for Visual Studio are removed for all versions. You can remap these file associations by using the Restore File Associations button on the Environment, General page of the Options dialog box.
For more information, see Visual Studio 2012 Compatibility.
.NET Framework Versions and Side-by-Side Installations
Visual Basic, Visual C#, and Visual F# projects use the Target Framework option in the Project Designer to specify which version of the .NET Framework a project uses. For a C++ project, you can manually change the target framework by modifying the .vcxproj file. For more information, see Version Compatibility in the .NET Framework.
When you create a project, you can specify which version of the .NET Framework the project targets in the .NET Framework list in the New Project dialog box.
For language-specific information, see the appropriate topic in the following table.