Some computers in our network have moved from Windows 2003 Server to Windows 2008 Server, and I found that a feature is no longer available which we used to replace applications (executable files) on the file server while users are working with them: to install new versions, it was possible to rename the current application file, and to copy the new file with the same name into this directory.
This has the nice advantage that we never needed a maintenance window and could apply patches very quickly.
I can remember from old Novell or early Windows ages that this feature was first available with Windows 2003 system.
Is this change in Windows 2008 a known change or is it configurable somehow?