Manually Running Offline/Boot Time Defragmentation

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Defragmenting System Files on a System (OS) Disk

Defragmenting System Files on Unlocked Disk

An offline defragmentation needs to be performed in order to defragment files that cannot be defragmented online and to optimize the file system (per Microsoft's recommendations) for fastest performance. Raxco Software recommends that you perform an initial offline defragmentation even if the files are not fragmented. Performing an offline defragmentation allows PerfectDisk to ensure that the Master File Table (MFT)/NTFS, metadata and other system files and directories are optimized for the best possible drive performance.

The offline defragmentation for system files on a OS drive is different than any other drive. These two methods are explained in the following two topics.

Defragmenting System Files on a System (OS) Disk

  1. When you click the Boot Time Defrag tool in the Tool Bar in PerfectDisk on a Windows system (OS) drive, you will go through the following dialog sequence:


  1. This indicates that, as expected, the System Files are in use on the drive. Clicking Cancel will do nothing. If you click Defrag on Next restart, you’ll then be prompted to reboot your system:


  1. You can click No to postpone the reboot until a time of your choosing, or click Yes to force an immediate reboot. If you elect to reboot immediately, the machine will reboot right away,

Defragmenting System Files on Unlocked Disk

The most common scenario for true offline disk defragmentation occurs on drives that the operating system doesn’t lock—this applies to all drives except for those where the operating system, the paging file, and hibernation files reside.

To defragment such a drive, select the drive in the Drive List, then click on the Boot Time in the Tool Bar. Alternatively, you can right-click a drive and choose Boot Time.


You get the following message:


Defrag on Next restart will show a message (shown in step 2 above) asking you to reboot the system.

Select the Optimize Drive Now button. This starts an analysis pass, followed by defragmentation.


Once the optimization is finished, the Statistics tab shows the statistics of the offline pass. An example is shown below:


Notice Excess Fragments Before and Excess Fragments After data for viewing the result of offline defragmentation.

Related Topics

§          Boot Time (Offline) Defragmentation

§          Scheduling Offline/Boot Time Defragmentation

§          What are Excluded Files

§          Choosing a Best Defragmentation Method

§          How to Maintain Peak System Performance?