AVG Signal Blog Performance Cleaning How to Fix 100% Disk Usage in Windows 10
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How do you know high disk usage is slowing down your PC?

You’ll feel it! It starts with a sense of general slowdown not caused by anything you’re actively doing. For example, if all you’re doing is browsing the web or opening a photo stored on your hard disk, and if those tasks take five to ten seconds instead of just one, then high disk usage is likely the culprit. Here are a few examples of when I know my hard disk is being used more than usual:

  • Opening a folder of photos and videos: The preview thumbnails take a long time to load, and the green bar at the top of Windows Explorer fills up very slowly.

  • Gaming: Loading a game or a new level takes noticeably longer, and there are occasional stutters. For example, the game randomly stops for one or two seconds as it’s loading new data into its memory, and the hard disk can’t keep up. 

  • Audible noises: Old-school mechanical hard disks are still quite noisy and make rattling noises when busy. If that happens, there’s some disk thrashing going on.

  • General lagginess: Weird lags when clicking on items, or opening menus or applications.

This article contains:

    A computer running Windows 10 at 100% disk usage is an inefficient computer — and that’s where AVG TuneUp can help. By cleaning out unneeded data, removing unwanted programs, and optimizing your PC with our patented, built-in Sleep Mode, AVG TuneUp reduces the strain on your hard disk and keeps your PC running like new.

    Use Task Manager to identify memory hogs

    The best way to identify why Windows 10 disk usage is at 100% is to consult the good old Task Manager. To do that, right-click on the taskbar and select Task Manager.

    Opening Task Manager from the taskbar on Windows 10.

    On the main dashboard, click on the Disk column to see all running processes sorted by the amount of disk usage they’re consuming.

    Using the Task Manager to identify programs with high disk usage.

    See the downward-pointing arrow in the Disk column? That’s the sign the processes are sorted properly. If an item turns orange and consumes more than a few megabytes per second, you know something is going on.

    Personally, I would look at anything that takes up more than 1 to 2 MB, because depending on the type of disk you’re using, even a small amount of excess disk usage can kill your performance. For example, on a seven-year-old HP laptop with an old mechanical drive, the maximum read and write speeds are about 40 to 50 MB per second. If a single process takes up 25 to 30 MB, you might see 100% disk usage on Windows 10 sooner than you expect.

    But my gaming PC has a super-fast NVME M2 SSD with transfer speeds of up to 5 GB per second:

    As seen in Task Manager, gaming PCs can have transfer speeds of up 5 GB per second.

    No matter whether your hard disk is slow or fast, anything that consumes more than a few MB per second for a prolonged period of time is unusual and worth looking into (regardless of the performance impact). 

    Note that if your PC feels slow and if disk usage isn’t an issue, then you might instead be suffering from high CPU usage or insufficient RAM.

    What causes high disk usage?

    If you’re at 100% disk usage with Windows 10, it might be due to a variety of reasons. There’s no one single cause for computer inefficiency. Often, your problem will be the result of several issues.

    If you think you know the reason, jump down below. Otherwise, keep reading for our more extensive list of possible problems.

    Synchronization tools

    Tools like OneDrive or Dropbox take time to synchronize all files. But I’ve seen both tools get stuck and cause constant hard disk thrashing because they were trying to synchronize when the actual process was done. That happens often with large amounts of data.

    In such cases, I often reset the programs or reinstall them. For example, you can reset OneDrive by pressing the Windows and R keys at the same time and typing in: 

    %localappdata%\Microsoft\OneDrive\onedrive.exe /reset 

    After clicking OK, OneDrive will reset and resync your files. This often solves issues with constant disk usage on my end. So check to see if it’s your sync tool clogging up your disk, and try a repair install to fix it.

    Windows update going wild

    Every few months, Microsoft releases new Windows 10 updates. Those download in the background and at some point install automatically. Since Windows is replacing literally tens of thousands of files, everything else will slow down during the update process. In some cases, Windows may even become unresponsive.

    To figure out whether an update is in progress, open the Start menu and click on Settings. From there, select Updates and Security. If you see the phrase “You’re up to date,” then you need to figure out what else could be causing Windows 10 to reach 100% disk usage.

    Windows Update popup showing you're up to date.

    But if the image you see looks like that shown below, with an update for some program downloading or installing, then you’ve isolated the problem. In this case, sit back and let Windows Update do its job.

    Windows Update popup showing a program update being downloaded and installed.

    Windows Superfetch fetching too much!

    Superfetch isn’t a strange canine superhero, but a Windows feature that’s a blessing to some and a horror to others. Windows Superfetch is supposedly a highly intelligent feature that Microsoft introduced in Vista. It analyzes your usage patterns, such as when you launch certain applications and how often, and then preloads their data into memory.

    In most cases, this works quite well, especially on older hard disks. But it’s not perfect. Some users complain that Superfetch causes constant hard disk usage. Gamers especially seem to hate Superfetch because it tends to preload the files of a game it thinks you want to play, while you’re instead playing a different game entirely. 

    If your hard disk is full, and if the following item shows up high on the list, you’re dealing with a Superfetch problem.

    Windows Superfetch causing high disk usage in Windows 10.

    In that case, I suggest disabling Superfetch to see if performance improves and that you don’t suffer any overall performance downgrades — it’s trial and error with this one. To disable Superfetch, press the Windows and R keys at the same time. Type in services.msc.

    Running Services in Windows 10.

    Hit OK. You’ll see a long list of services that Windows is running. Scroll down until you see SysMain.

    Viewing the Superfetch service in Windows 10.

    Under Startup type, click Disabled and hit OK. Reboot your system and see if performance improves. As mentioned, there’s no guarantee. If it didn’t help, you should probably turn Superfetch back on again.

    A virus gone berserk

    Is Task Manager showing you an unknown program with super-high disk usage? If a Google search doesn’t uncover anything useful, it might be a virus — time to learn how to get rid of viruses or malware on your device. There might also be spyware on your system. At any rate, make sure you stay updated about the most dangerous current threats, and read our list of best security and privacy tips.

    Since malware can play a huge role in pushing Windows 10 to 100% disk usage, stop whatever you’re doing now and install a free antivirus tool. We recommend AVG AntiVirus FREE, which not only provides real-time security updates, it also scans your machine for both malware and performance issues.

    A malfunctioning antivirus product

    High disk usage can also be caused by your antivirus software — during a background scan, or if the tool suffers a malfunction and gets stuck. Go into your antivirus tool’s dashboard to see if a scan is in process. If so, do not stop it.

    If the scan seems frozen, reboot your system and let it sit for a while until the antivirus stops. If it doesn’t stop, then you might need to reinstall the antivirus or find another one. AVG AntiVirus FREE is a resource-light solution that you can try right now.

    A lot of active applications

    Having a lot of applications installed and running on your PC at the same time may cause 100% disk usage in Windows 10. And uninstalling these programs often isn’t possible, because you may need them.

    AVG TuneUp’s Sleep Mode identifies these resource-intensive applications and deactivates them when you’re not using them. For instance, Adobe Reader runs various background tasks, and these might lead to high disk usage. Another example is TeamViewer — if you’re not currently using it to access another PC, there’s no reason for it to run in the background.

    AVG TuneUp — and its built-in Sleep Mode — detects these programs, turns them off, and reactivates them when they’re needed. Once you launch Adobe Reader, Sleep Mode turns everything back on again as if nothing happened.

    Try Sleep Mode out for yourself. Download and install AVG TuneUp, then go to Speed Up and click on Background & startup programs.

    Using Sleep Mode in AVG TuneUp.

    A defective hard disk

    A structural or physical defect can also be responsible for 100% disk usage in Windows 10. To check your disk for errors, try AVG Disk Doctor, another custom built-in feature in AVG TuneUp.

    To launch Disk Doctor, open AVG TuneUp and click on the All functions option in the Action Center. Fire up Disk Doctor and run a check.

    The Disk Doctor tool in AVG TuneUp

    If it finds an error, it will fix it automatically. But if Disk Doctor doesn’t work, or if it keeps attempting to fix an issue, then you might be looking at a defective hard disk. To prevent data loss, get your files off that disk as quickly as possible. Copy them to an external hard disk and replace the drive with a new one.

    A damaged page file

    Whenever your PC runs out of free memory (RAM), it uses a “page file” on your hard disk to expand its memory. Let’s say you’re editing a 10 GB video file, but you have only 8 GB of memory (at least 2 to 3 GB of which are taken up by Windows and your apps). Your PC will use the page file on your disk as expanded memory. 

    Over time, this page file can become defective, which can, in turn, cause unexpected slowdowns and high disk usage. To fix it, you need to delete that page file and create a new one. To do that, press the Windows and R keys at the same time and type in sysdm.cpl.

    Opening System Properties to manage paging file size.

    Click OK and go to Advanced > Performance > Settings > Advanced > Change. Uncheck Automatically manage paging file size for all drives and then select No paging file. Hit Set and then reboot your system.

    Repeat all those steps again, select System managed size, and hit Set. Then, check Automatically manage paging file size for all drives.

    Changing virtual memory and page file in Windows 10.

    Windows Search index won’t stop indexing

    The index in Windows Search helps you find files, folders, emails, and even the content of some of those files instantly. To do that, it scans your hard disk and turns it into a super-fast index to give you immediate results.

    Unfortunately, I’ve experienced the search feature losing control as it keeps on indexing, indexing, indexing, indexing, and indexing even more, with no end in sight.

    In such cases, it’s best to fully rebuild the index. Click on the Start button and type in Indexing. The search results will return this:

    Launching indexing options to rebuild the Search Index in Windows 10.

    Click on Indexing Options. From there, select Advanced and hit the Rebuild button. That will completely erase the index, rebuild it, and hopefully fix any errors that cause hard disk thrashing.

    Bugs with temporary files

    Temporary-file bugs are a rare occurrence, but I have witnessed them recently. A Windows process or application was randomly creating temporary files nonstop. We’re talking hundreds of thousands of 1 KB files that were created and deleted, likely caused by a bug.

    A bug with temporary files in Windows 10.

    Deleting these files helped fix this odd issue. To regularly clean up temporary files, download AVG TuneUp and give its disk cleaning functionality a spin. It’ll scan your machine for junk files and bloatware, letting you safely delete them and optimize your computer for the best possible performance.

    An outdated driver 

    Drivers control all the hardware in your computer, including your hard disk controller and the hard drive itself. Perhaps there’s a bug in a driver that’s pushing Windows 10 to 100% disk usage. It’s best to make sure you have the latest drivers installed.

    To do that, get our new AVG Driver Updater and run a free scan. AVG Driver Updater’s easy-to-use interface will help you find and update your outdated or broken drivers, fix your problems, and return your computer to optimal performance.

    Driver Updater in AVG TuneUP scanning for outdated drivers.

    Fix 100% disk usage in Windows 10 caused by outdated hard drive firmware

    There’s software inside your hard drive as well, known as firmware. Recent firmware releases can help fix performance issues or unnecessary read/write operations. You’ll need to check if there’s an update available, but first, figure out which hard drive you actually have (if you don’t already know).

    Right-click on the Start button and select Device Manager. Expand the Disk drives section and look at the exact names of your drives:

    Find the exact names of your disk drives.

    My main drive is the Samsung SSD 970 EVO Plus. So, in this example, I’m visiting Samsung’s support pages to see if there’s an update available — and voila! There’s new firmware available.

    Updating firmware through Samsung's support pages.

    Can running Windows 10 at 100% disk usage damage my disk?

    If your Windows 10 disk usage is at 100% for a long period of time, you might see permanent damage. But there’s nothing wrong with 100% disk usage for a few minutes or even an hour. But if your disk is constantly at maximum capacity, and if this persists for several days at a time, things may take a turn for the worse. Constant disk usage increases the temperature and thus the chance that your disk will fail at some point.

    Mechanical disks have a physical head that moves across the disk to read and write to it. Sustained 100% usage can lead to mechanical failure. On a modern SSD, the lifespan of the individual cells can decrease if you’re constantly writing and deleting data.

    It’s unlikely that you’ll experience data or hardware loss in the short term, but it’s definitely a possibility if this keeps on going. You should identify and eliminate the culprit as soon as possible.

    Low memory and high usage

    As discussed above, once your PC runs out of RAM, it uses a virtual page file on your disk. If you don’t have enough RAM to support the programs you use, you’ll force your PC to constantly dip into this page file. That happens especially with 4 GB of RAM or less. In that case, you may want to update your RAM.

    How not to fix Windows 10 at 100% disk usage

    Finally, there are a lot of tips and tricks out there to fix high disk usage. While some of them are useful, others are flat out dangerous and unhelpful.

    • Disable antivirus: No! You’re putting yourself at risk. If your antivirus is causing high disk usage, check out our antivirus advice from earlier in this article

    • Disable disk defragmentation or turn it off: No! If a defragmentation process is going on, Windows will pause it while you’re working. Let it do its thing while you’re not working, and do not turn it off.

    • Disable Windows Update: Um, that’s a big no! Windows Update itself is not causing your disk to run at 100% capacity.

    Giving your hard disk a rest

    Hopefully together we’ve gotten rid of all the potential causes of your hard disk going nuts. To prevent it from happening again, it’s critical to uninstall programs you don’t need, clean up files, and make sure that background processes don’t bog you down. 

    AVG TuneUp will automatically take care of all of that, cleaning out all the unnecessary software, waste-of-space files, and other inefficiencies getting in the way. It’s an all-in-one tool dedicated to restoring your PC to prime performance — and making 100% disk usage a thing of the past. Try it free for 30 days.

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