To defrag Windows 8.1, type "defragment" into the search bar on the Start screen, and then select Defragment and Optimize Drives from the list of results. Run the program's disk analysis, select specific or all partitions, and click Optimize to begin defragmenting drives.
By default, the Optimize Drives program runs automatically on a weekly schedule, but users can change this in the Defragment and Optimize Your Drives setting menu. To turn off the scheduled optimization, clear the Run on a Schedule check box. To change the frequency of the scheduled optimization, click the drop-down list next to Frequency and select either daily, weekly or monthly optimization. To choose which drives to include in the scheduled optimization, click Choose next to Drives, and select the desired drives.
The disk defragmenting tool in Windows 8.1 is different from that in previous versions of Windows. The tool, which was called Disk Defragmenter in Windows 7, is called Optimize Drives in Windows 8.1. With the name change came a few tweaks in some of the inner workings of the program.
Users can choose to defragment Windows using a downloadable program such as Defraggler. Defraggler offers full customization and scheduled defragmentation. The Piriform website provides a free Defraggler download and instructions for using the program.