.LIBRARY-MS File Extension

Operating system file introduced with Microsoft Windows 7; appears as a subfolder within the Libraries folder in the left side panel of the Windows Explorer; includes references to one or more folders that can be browsed when the library is opened.

LIBRARY-MS files are used for creating virtual folders with collections of similar files. For example, Windows 7 creates Documents, Music, Pictures, and Video libraries by default. You can create custom libraries by right-clicking the Libraries folder and choosing New → Library. When you open the new library, Windows provides an Include a folder button that you can click to add folders to the library.