How to: Unload the Projects in a Solution Folder
You can make all the projects in a Solution Folder temporarily unavailable within a solution, and then restore these projects to available status. When you unload the projects in a Solution Folder, the Solution Folder remains visible in Solution Explorer. Alternatively, you can hide a Solution Folder so that all the projects and items that it contains are not visible in Solution Explorer but are still available in the solution. For more information, see.
To unload the projects in a Solution Folder
In Solution Explorer, select the Solution Folder you want to unload.
On the Project menu, choose Unload Projects in Solution Folder.
The projects are now marked (unavailable).
To reload the projects in a Solution Folder
In Solution Explorer, select a Solution Folder that contains a project that is marked (unavailable).
On the Project menu, choose Reload Projects in Solution Folder.
All the projects are available for editing and inclusion in configuration and build processes.