You are using a Distributed File System Namespace (domain based or standalone)
You are using a Sharepoint Foundation Server
You configured a DFS link to point to your Sharepoints Webdav share with a Folder Target such as \\Server@port\DavWWWRoot\Share\Folder
You use the DFS path (i.e. \\Contoso.com\DFS\Link-to-Sharepoint) to access Data on the WebDav share.
In this scenario, when you use a Microsoft Office Application to open files from the Sharepoint Webdav Share by using the DFS path and you make changes to the files, the files remain locked for extended periods of time after saving the changes and closing the files.
Therefore every user that tries to open the file during this time will be presented with a dialog simillar to this:
"This file is locked for editing by %Username% Do You want to: o View a read-only copy o Save and edit a copy of the file o Receive a notification when the server file is available."
Opening and Saving Files with other Applications such as Notepad is not affected. The Problem does not ocurre if the WebDav Path is used instead of the DFS path.
Saving files from an Office Application works differently depending if the file is saved against a File Server Share (by SMB or SMB2) or a Sharepoint Server (by WebDav over http or https). Additionaly the maintenance of file locks and temp files work different depending if the target share is a file server share or a WebDav share on a Webserver / Sharepoint Server.
In the scenario above the user provided Office with a DFS path to access the file (\\Contoso.com\DFS\Link-to-Sharepoint). Therefore Office behaves as if it would save a file against a file server share while in fact it is working against a Sharepoint Server (\\Server@port\DavWWWRoot\Share\Folder).
Due to the different file saving (handling of .tmp files) and file locking mechanic against a file server share Office and Sharepoint cannot interact properly with each other and the file remains blocked for write access after closing it until some point later when the sharepoint server determines that the file can be released.
Office 2007, Office 2010, Sharepoint, Distributed File System, Namespace, WebDav, Save file, Read Only, Word, Excel, Powerpoint