Projected File System (ProjFS) programming guide

The Windows Projected File System (ProjFS) allows a user-mode application called a "provider" to project hierarchical data into the file system, making it appear as files and directories in the file system.

In this section

Topic	Description
Provider Overview	Conceptual overview of a provider application.
Cache State in the Virtualization Root	Describes the different cache states a file or directory managed by the provider may have.
Enabling Windows Projected File System	Describes how to enable the ProjFS optional component.
Virtualization Instance Lifecycle	Overview of the lifecycle of a ProjFS virtualization instance.
Enumerating Files and Directories	Describes how a ProjFS provider participates in directory enumeration.
Providing File Data	Describes how a provider supplies placeholder info and file data.
File System Operation Notifications	Describes how a provider can receive notifications of file system operations.
Handling View Changes	Describes how to update the client view of a provider's backing store.
Asynchronous Callback Handling	Describes how the provider can asynchronously service callbacks.
Windows Projected File System API Reference	Reference information for the ProjFS programming interface.

Additional Resources

Topic	Description
RegFS Sample	A sample ProjFS provider that projects the Windows registry into the file system.