The Disk Defragmenter in Windows 8 is set to run on a regular basis by default, which means that you don’t really need to open and run it manually. But if you have trouble running the in-built defragmenter tool and you maybe, get error messages like Disk defragmenter could not start or Failed to initialize, you should be aware that your Disk Defragment is not working.

In this article, there are a few solutions you may want to try to solve this problem on your Windows 8.

Solution 1 Get a Disk Defragmenter

The easiest way to solve this problem is to get a powerful disk defragmenter. Neptune SystemCare Ultimate sees a much higher fragmentation than Windows Disk Defragmenter because it evaluates more files than the Windows tool, which offers a disk fragmentation map, a list of fragmented files and health data for your hard disk.

->Download and install Neptune SystemCare Ultimate.

->Launch and go to System Tuneup>Disk Defrag, click Defragment and wait. Disk Defrag would do the rest.

Solution 2 Check Disk Error

You can check the disk errors through Command Prompt.

->Press Windows + R on the keyboard to open Run box and type cmd.exe in. Or, go to Start > Accessories > System Tools > right-click Command Prompt and select Run as administrator.

->Type chkdsk /r, and type Y when asked if you want the disk checker to run the next time the computer is started.

->Reboot your computer and try to defrag again.

Solution 3 Check Free Space

It is not surprising that not enough free space can fail to open Disk Defragmenter. Make sure you have at least 15% of the space on your hard disk free.

->Go to This PC or My Computer, right click on the hard disk and choose Properties.

->Check that the percentage of free space indicated is at least 15% - preferably 20% and more.

Solution 4 Defrag in Safe Mode

Restart your computer and press F8 repeatedly after the boot screen to start Windows in Safe Mode. If your disk defragmenter can run in Safe Mode, this provides additional information to help diagnose what the problem is with a normal Windows start.