A. I've heard of cases in which the disk defragmentation engine stops functioning, resulting in several problems, such as:

• When you attempt to Analyze or Defragment, Disk Defragmenter performs no actions.
• When you try running Defrag.exe from a command line or batch file, you receive a Windows cannot connect to the Disk Defragmenter engine error message.
• When you right-click a local hard disk and select Properties, the Defragment Now button isn't available on the Tools tab, or if it is available, pressing it displays the following error message: "The Disk Defragmenter is not installed on your computer. To install it, double-click the Add or Remove Programs icon in Control Panel, click the Install/Uninstall tab, and then follow the instructions on your screen."

To resolve the problem, force a reinstallation of the disk defragmenter engine:

1. Navigate to the %SystemRoot%\INF folder (Start, Run, %SystemRoot%\INF) and click OK.
2. Right-click the dfrg.inf file and press Install.