You should never defragment a solid-state drive (SSD) as it can shorten its lifespan.
In Windows 7, the built-in Disk Defragmenter utility runs automatically at scheduled times, usually once per week and if it missed it’s schedule, it will run the next time when the computer is idle.
To disable the scheduled defragmentation in Windows 7, click Start, type disk, and then select Disk Defragmenter. Click Configure schedule to disable the feature.
Windows 7 runs a simple benchmark on the drive and if it is faster than 8 MB/sec, Window 7 deems it an SSD and no defrag will occur even though it’s enabled.
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