Don't defragment if you are using an SSD:
[Please never defrag SSD data as it already has a built-in automatic maintenance process. Therefore, it is not necessary to defrag a solid-state drive to boost performance. Since SSD does not use a rotation motor to fetch data from disk, it is not required.]
1. Click on the Start menu.
2. Then search for Defragment and Optimize Drives.
3. Click on the Optimize drives data.
4. Select Disk for the Optimization process.
5. Then you have to first analyze the disk after completion of drive analysis, If current status is OK then you don't need to optimize the drive but If optimization is require then it will show you inside current status.(example: External backup Drive - Needs optimization) after that you will have to click on optimization button.
6. Then the process will begin.
7. Drive will be successfully defragmented.
It will be re-organizing the location of the files & speed up disk access on spinning disk media for large files that have become non-contiguous on the disk surface.