Constant high disk usage is a common problem among Windows users.
The typical signs of the issue include extremely slow operations, high load times, and even disk failure.
Your programs and Windows also become laggy and unresponsive at times.
Most users are baffled by what causes these issues because it can be hard to pinpoint the real culprit.
Read on as we explore the potential reasons your disk usage is always at 99% and what you can do about it.
Why Is My Disk Usage At 99? (Causes, Fixes)
The causes for 99% disk usage range from virus infections, corrupt software, and Intel’s Rapid Storage Technology to virtual memory misconfigurations, auto-scheduled Windows defragment tasks, and Windows search indexes.
To identify the root cause, you need to view your Windows Task Manager and Resource Monitor.
These tools let you see how much disk capacity each process is using.
Once you pinpoint the process consuming your disk capacity, you should end it and check your disk usage again.
If the issue persists, you’re probably dealing with a Windows or firmware-level problem that requires more digging.
Below, we’ll cover the different solutions you can try to resolve your 99% disk usage problem.
How To Identify The Process Consuming Your Disk Capacity
Although the high disk usage problem might seem puzzling, most of the time, it’s not difficult to see which app is eating up all your disk capacity.
That’s because Windows comes with the appropriate diagnostic tools: Windows Task Manager and Windows Resource Monitor.
1. Windows Task Manager
The task manager gives you an overview of your computer’s general resource usage and the services and processes running on it.
To open it, right-click on the Start menu in your taskbar and click Task Manager.
Alternatively, press Ctrl + Shift + Esc to open the task manager.
If the opened window is small, click on More Information to get the full-sized task manager.
Once there, you can sort your processes based on their consumption of disk capacity.
Click on the Disk Usage column header and see the first process.
Then right-click on that process and click End Task.
If that does the trick, you need to take action to fix the issue permanently because it most likely will reappear once you restart your computer.
The general approach is to search the name of the process you just killed to see what it does and how you should deal with it.
Nonetheless, here are a few specific recommendations for the most common situations.
2. Internet Browser
If Chrome, Firefox, or any other browser is pushing your disk usage to the max, the first solution to try is to update the browser.
However, the more likely cause is a poorly coded extension or add-on.
First, kill all the processes corresponding to the browser.
Then type in your browser’s name in the Start Menu and choose New Incognito Window (aka Private browsing in Firefox).
Check the Task Manager to see if your disk usage goes back up.
If it does, completely remove the browser with a tool like Revo Uninstaller, download the latest version of the browser from its official website, and install it again.
Otherwise, you need to identify which extension is causing the high disk usage problem.
Starting from the most recent one, remove the extensions one by one, and restart your browser every time until the issue goes away.
3. Windows Services
Windows services are small programs that manage core aspects of the operating system, such as audio playback and the clock.
Sometimes, these services get corrupted and conflict with one another.
If the process causing your issue is a Windows service, you have to see how your computer is affected by killing it.
Google the service’s name to find out what it does.
Then decide whether or not you can live with the consequences of killing that service.
For instance, the Windows Audio service is responsible for playing sounds and music on your computer.
Therefore, when you kill it, you can’t play music, videos, or games on your computer until you restart the Windows.
To prevent a Windows service from automatically starting after every reboot, follow these steps:
- Open the Start Menu and type in Services. (Alternatively, you can press the Windows key + R and type in services.msc.)
- Locate your intended service from the list.
- Right-click on the service and click Properties.
- From the Startup Type dropdown menu, select Manual.
- Click OK.
This way, you can start the service whenever you need it by locating it under services, right-clicking on it, and selecting Start.
Although it might be a hassle, this approach will save you from having to do a clean Windows installation.
4. Critical Windows Component
Sometimes, the process that’s using up your disk capacity is a critical Windows process such as svchost.exe.
The Task Manager doesn’t allow you to kill those processes because they’re necessary for the operating system to keep functioning normally.
In this case, your best bet is to do a clean boot (more on that later) and see if your problem goes away.
If so, you can pinpoint the cause by removing your drivers and programs one by one.
Or you can do a clean Windows installation and save yourself the headache of troubleshooting programs and drivers.
5. Windows Resource Manager
Unlike the Task Manager, the Resource Manager utility lets you look under the hood of your Windows.
You can see how many bytes of data are written and read to each disk in real-time.
It also shows you detailed info on the processes using your disk.
To open the Resource Monitor, press the Windows key + R and type in resmon.exe.
Click on the Disk tab and then the Read (B/sec) column to sort the process by how much data they read from your disk, which directly determines their disk usage.
Once you identify the process causing your issue, the procedure to follow is the same as we explained above.
6. Clean Boot Your Windows
Some Windows processes (and some sneaky malware) don’t appear on the Task Manager or the Resource Monitor.
However, these are usually uncritical Windows components, and they’re more prone to getting corrupted.
Fortunately, Windows comes with a mode that disables these components and only allows the most basic parts of the operating system to load with minimal drivers.
This feature is called the clean boot.
It’s similar to Safe Mode, but it gives you more control over the third-party apps and drivers that load on startup.
You can perform a clean boot as a way to diagnose your problem and isolate the cause.
If the issue persists, your best bet is to reinstall your Windows from scratch and hope that you’re not dealing with a hardware problem.
If the problem isn’t present after a clean boot, you may be able to fix it with some more digging.
Here are the steps to performing a clean boot:
- Press the Windows Key + R and type in msconfig.
- Navigate to the Services tab.
- Check Hide all Microsoft services and click Disable all.
- Navigate to the Startup tab and click Open Task Manager.
- Go through the list and click Disable for all the items.
- Close the Task Manager.
- Click OK on the Msconfig dialog.
- Restart your computer.
Once your computer loads, check the disk usage on the Task Manager.
If the problem disappears, start enabling the services and apps you disabled before.
Enable one service, restart the computer, and check the usage.
You should wait a few minutes to make sure the Windows has fully loaded before deciding if the problem is gone.
This incremental process lets you pinpoint the program or component causing the issue.
However, if the problem persists, return all your disabled apps to their previous state and check the remaining solutions.
7. Uninstall Intel’s Rapid Storage Technology
Intel-based computers usually come preinstalled with a program called Rapid Storage Technology, which claims to increase performance and reliability with SATA hard drives.
It also reduces power consumption and increases battery life on laptops through Link Power Management.
However, that exact feature sometimes causes your disk usage to max out.
To fix it, go to the app’s settings and turn off Link Power Management.
It’ll reduce your laptop’s battery life by a few minutes, but you’ll save your HDD from being constantly active.
Another option is to uninstall Rapid Storage Technology all together.
Windows already has the necessary features to efficiently communicate with hard drives and SSDs.
Therefore, any gains from additional software will be minimal at best.
However, after removing RST from your computer, go to your UEFI BIOS utility and set your HDD connection type to Advanced Host Controller Interface (AHCI) if it’s on IDE.
This change enables a faster connection between your disk and your Windows.
8. Check For Viruses And Malware
It’s common for malicious software to wreak havoc on your system’s resources, including pushing your hard disk to the edge.
Sometimes, they use your system resources for other purposes, such as mining cryptocurrency.
Other times, they just run futile operations.
If you don’t already have one, install an antivirus suite that offers antimalware protection.
Then do a full scan of your system files.
Note that the scan will take a relatively long time because your system’s hard disk usage is already high.
If the scan identifies malicious software, it’ll most likely quarantine the executable files, and your disk usage will return to normal.
Another great option for this situation is Microsoft’s Safety Scanner, a lightweight malware removal tool that you can quickly install.
You can even run the tool from a thumb drive if the malware prevents you from installing it on your Windows.
The scanner is a different tool from Windows Defender, so you’ll have to download and install it separately.
You should always download the latest version from Microsoft’s official website as each download is only valid for ten days.
9. Manually Configure Your Virtual Memory
Virtual memory is a critical component of Windows that acts as a hidden file (pagefile.sys) stored on your hard drive.
It’s as large as your entire RAM capacity (e.g., roughly 16 GB if you have 16 GB of RAM installed).
Virtual memory stores the information moved into the RAM that hasn’t been used in a while.
This way, the operating system frees up space on your RAM for newer information.
If the old information is ever needed, some other dated information is moved out of the RAM, and the data in pagefile.sys is moved back in.
As you can imagine, the process is complex and requires different operations.
The file is divided into multiple smaller units called pages to make data management operations easier.
The page size varies between 16 MB and multiple times the size of your physical memory.
Windows automatically detects the ideal size based on how much RAM you have available.
However, the calculations are sometimes wrong, and Windows ends up endlessly swapping files in and out of your hard disk, which translates into 99% disk usage.
To remedy the situation, you need to set the page size manually.
Here’s how to do that:
- Open Control Panel.
- Navigate to System > Advanced system settings.
- Under the Advanced tab, find the Performance section and click Settings.
- Again, navigate to the Advanced tab, find Virtual Memory, and click Change.
- Uncheck “Automatically manage paging file size for all drives.”
- Select your Windows drive.
- Click Custom size.
- Set the Initial size to your physical RAM.
- Set the Maximum size to twice the size of your physical RAM.
- Click Set and then OK.
- Restart your computer.
10. Disable Auto-Scheduled Windows Defragment Task
Defragging your hard drive reorganizes how files are stored such that the pieces of a file are put closer to each other.
As a result, your disk’s optical head doesn’t have to travel very far to retrieve an entire file.
The defragging process can be time-consuming and intensive on your disk because it involves moving many file sectors around.
If the defragment process is performed regularly, your disk usage can go high and even up to 99%.
You should check to see if a defragmentation task is scheduled to run on your computer at predetermined intervals.
To view the scheduled tasks on your computer, navigate to Control Panel > Administrative Tools > Task Scheduler.
Once there, look at the folder structure on the left-hand side and expand the following path:
Task Scheduler (Local) > Task Scheduler Library > Microsoft > Windows > Defrag.
Double click Defrag to see the auto-scheduled tasks.
If the Trigger or Next Run Time fields aren’t empty, your hard drive gets defragged regularly, which could cause your high disk usage.
Select the task and then click Disable from the right-hand sidebar.
Restart your computer, wait a few hours and check your disk usage again.
Warning: If you have an SSD, you shouldn’t defrag it because doing so won’t increase your speed. However, because SSDs have a limited number of read/write cycles, it’s better not to waste your limited capacity on a tool that isn’t designed for SSDs.
11. Disable Windows Search
Starting from Windows Vista, Microsoft expanded Windows search functionality to instantly search every folder on your computer.
Although the feature is extremely convenient, it requires creating large address books of your files, called indexes.
Generating those indexes and keeping them up-to-date requires frequently reading your files, which means high disk usage.
You can disable the Windows search feature to see if it resolves your problem.
Here are the instructions to follow:
- Press the Windows Key + R and type in services.msc.
- Locate Windows Search.
- Double-click on it and press Stop.
- If you want to permanently disable the service, choose Disabled from the Startup type dropdown menu.
- Click OK.
- Restart your computer.
Alternatively, you can disable the search indexing feature.
You’ll still have the search functionality, but running queries will take longer because your file addresses aren’t stored in an index optimized for speedy retrieval.
Follow these steps to disable search indexing:
- Open This Computer.
- Right-click on your Windows drive (usually Drive C).
- Select Properties.
- Remove the checkmark from “Allow files on this drive to have contents indexed in addition to file properties.”
- Click Apply.
- From the dialog that pops up, select “Apply changes to drive, subfolders and files.”
- Click OK.
Allow the process to finish.
Then restart your computer.
Check your disk usage after a few minutes to see if the problem is gone.