Deleting a solution permanently erases files from physical storage as well as the file items in the solution.
In contrast to projects and items, a solution can only be deleted permanently, not removed temporarily.
To delete a solution
In Solution Explorer, select the solution you want to delete.
On the File menu, click Close Solution.
In Microsoft Windows Explorer, locate and select the files associated with the solution you want to delete.
On the File menu, click Delete.