Category: 2008 R2

For SBS 2011 and Server 2008 R2, this Microsoft article has a fairly quick walk-through of the required steps.

TL;DR version:

To view and close open files

1. Open the Server Manager
2. In the Actions pane, click Manage Open Files
   • To close a specific file, select the file and click Close Selected
   • To close all files, click Close All