In case, the defrag facility is not working on your Windows 10 PC due to an error, the SFC command will scan for the error and help resolve it. In the Windows search bar, type cmd Choose Run as administrator from the right-hand side When the command prompt window opens, type sfc /scannowIn case, the defrag facility is not working on your Windows 10 PC due to an error, the SFC command will scan for the error and help resolve it. In the Windows search bar, type cmd Choose Run as administrator from the right-hand side When the command prompt window opens, type sfc /scannowpartitionwizard.comИзображение:partitionwizard.comDefrag won’t run in Safe Mode – Several users reported that they can’t defrag their drive in Safe Mode. This usually happens if your installation is corrupted. If SFC or DISM scan can fix this problem, you might have to reinstall Windows 10.
How to fix Disk Defragmenter error in Windows 10?
1 Fix 1. Check the Disk Defragmenter Service 2 Fix 2. Stop Other Running Applications 3 Fix 3. Run System File Checker 4 Fix 4. Check and Fix Hard Drive Errors 5 Fix 5. Use Disk Defragmenter in Safe Mode 6 User Comments
How to fix defdefrag not working on Windows 10?
Defrag not working Windows 10 could be caused by the errors on your hard drive. In order to fix this issue, you need to check and repair hard drive errors. CHKDSK is a useful tool that can help fix disk errors. Here’s a simple guide to use it.
Why can't I DeFRaG Windows 10 in safe mode?
Defrag won’t run in Safe Mode – Several users reported that they can’t defrag their drive in Safe Mode. This usually happens if your installation is corrupted. If SFC or DISM scan can fix this problem, you might have to reinstall Windows 10.
Where is the Disk Defrag command?
Disk Defrag should be under Windows Administrative Tools. You can also run from doing Winkey+R with defrag in the bpx and press enter. He was missing the Service, not the command. A couple of SFC /scannow fixed it.

Below are two helpful articles on a similar topic 👇
What is defragmenting and why is it important?What is Defragging and how does it work?