How and When to Defragment Your Hard Drive in Windows 10

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Over time, files on your hard drive get fragmented, and your computer slows down because it has to check multiple places on your drive for those pieces. To have your computer run more efficiently, use the built-in tool in Windows to defragment those files. Here's how and when you should do it.

Windows 10, like Windows 8 and Windows 7 before it, automatically defragments files for you on a schedule (by default, once a week). However, it doesn't always run consistently, so if you notice files are taking longer to load or you just want to double-check every month or so, you can see how fragmented the drive is in Windows.

windows10 defragmented

A note about Solid State Drives (SSD): SSDs work differently than traditional mechanical hard drives. Conventional wisdom is that SSDs don't need to be defragmented and doing so can also wear down the drive. However, Windows does defragment SSDs once a month if necessary and if you have System Restore enabled. This isn't something to worry about, though, because the automatic defragmentation is meant to extend your drive's life and performance.

So with SSDs, just let Windows do its thing and don't worry about defragmentation. You can use the Optimize Drive tool below to do a general optimization of the drive, including sending the TRIM command to optimize performance. This doesn't do a traditional defrag on the SSD, though. For your mechanical drives, you can check and fix its fragmentation status with the steps below.

1. Open the disk optimization tool by searching for "optimize" or "defrag" in the taskbar.

windows10 search optimize2. Select your hard drive and click Analyze. Note that if you have a SSD, this option is grayed out and not available.

windows10 analyze3. Check the percentage of fragmented files in the results.

windows10 analyze results

There's no hard and fast rule about how fragmented your drive should be before you defrag it. You might want to keep your fragmentation percentage under 5% or so, however, so that the defragmentation process doesn’t take too long to finish.

4. If you want to defragment your drive, click Optimize. It's best to do this when you don't need to use your computer for anything else, so you can let Windows defragment the drive efficiently.

windows10 optimizeWhen Windows is done, your drive should say 0% fragmented in the Optimize Drives utility.

Add a comment
  • Marcia Says:

    What if under Optimize drives it says solid state but under current status it says not available. What do I do about defragging?

  • johnec Says:

    Windows 10 won't let me into defrag, says Have to be Administrator account while I am on Administrator account.

  • MickeyMouse Says:

    Guys just use programs designed for it... like UltraDefrag or something... don't ever let Microsoft do something for you... Do it yourself as it should be done!

  • Wilson Says:

    My system said
    19% fragmented I hit Optimize. It stills says
    19% fragmented. How can I reduce it to 5-10% ???? Or is this not possible. Thanks

  • Annie Says:

    I'm not able to de-fragment the C: drive,it shows 29% fragmented.
    What can I do?

  • Jack M Says:

    The above assumes that the optimize works. I have attempted to run it several times and have gone from 10% to 15% fragmented. It seems as though there is no rhyme or reason to how this works and I am tired of spending 30 to 45 minutes every time to have no impact on my hard drive. MS customer service says to buy their support package and then they will talk to me. Another plus for the wonderful OS foisted on us!

  • Pat Singleton Says:

    My computer keeps freezing up. What must I do? It says I'm automatically set to defragment weekly.

  • Christi Carey Says:

    This discussion was helpful. Windows 10 has caused my computer to reboot 30 times over the last 2 months and I know there were file fragments causing problems. Computer has also frozen 10 times at least. I wish Microsoft cared. I have lost hours of work.

  • Keith Henderson Says:

    A drive labeled "System" indicates it is 39% fragmented and needs to be defragmented. I click "Analyze" and the result is 79% fragmented. I then click "Optimize" and the result goes back to 39% fragmented. How do I defragment that drive?

  • Robert Gustafson Says:

    I followed the instructions. When I clicked analyze, my system disk was 45% fragmented. I clicked optimize and the fragmentation went from 45% to 22% instantaneously. I clicked optimize again and it came back with 22%. I clicked optimize again and had the same result. What should I do now?

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