User information file created by Visual Studio 2012, a software development tool used for creating Windows programs and Web applications; contains user information for a project such as expanded nodes, opened tool windows, and user tasks; structured in a binary format.

The file is used to maintain appearance continuity from when you closed the project and then when you reopen it. The file is referenced by VSPackages created with Visual Studio, opened by the LoadUserOptions Method, and modified by the WriteUserOptions and SaveUserOptions methods. The compound extension ascends with each new version of Visual Studio. Visual Studio 2013 uses the .V12.SUO extension. NOTE: The V11.SUO file can be deleted to boost Visual Studio's performance but you will lose the user solution data contained in the file.