You want to find the open files on a system.
There are two different categories of open files on a system. Since the days of Windows NT, the operating system has supported the capability to view the files that are open from shared folders. This is useful when you want to see who is accessing files on a file server, especially if you need to take the system down for maintenance and you want to notify the impacted users.
First seen in Windows XP and supported in Windows Server 2003 is the ability to view all open files on a system (not just shared folders). To use this feature, you first have to enable support for it. The reason this isn't enabled by default is because there is a slight systemwide performance impact when tracking all open files. To enable support for it, run the following command:
> openfiles /local on
Using a graphical user interface
None of the standard graphical tools provide a list of the open files on a system. The closest thing to it would be the Sysinternals File Monitor tool. For more information see Recipe 8.21.
To view the open files from shared folders, do the following: