If your Task Manager shows Disk at 100% and your PC is extremely slow, you’re not alone. This problem is very common, especially on systems with HDDs, and it is NOT fixed by random YouTube tricks. Below is the real, proven solution, step by step.
🔎 Why Does 100% Disk Usage Happen?
The most common causes are:
- Slow or old HDD (mechanical hard drive)
- SysMain (Superfetch) and Windows Search services
- Incorrect or outdated SATA / Storage drivers
- A failing disk (SMART errors)
- Windows Update running or stuck in the background
🔧 STEP 1: Disable SysMain (MAIN FIX)
SysMain (formerly Superfetch) is a Windows service that tries to speed up app loading by preloading frequently used programs into memory.
On many computers, especially those using traditional HDDs, this behavior actually causes constant disk activity and leads to 100% disk usage.
Disabling SysMain is completely safe, does not break Windows, and does not affect updates, security, or system stability.
At worst, some apps may open a fraction of a second slower, but in most cases the system becomes smoother, quieter, and more responsive.
Method 1 – Using Services (RECOMMENDED)
- Press Win + R
- Type
services.mscand press Enter - Find SysMain
- Double-click it
- Click Stop
- Set Startup type to Disabled
- Click Apply → OK
- Restart your PC
Method 2 – Using Command Prompt (Admin)
- Press Win + X → Command Prompt / Terminal (Admin)
- Run these commands one by one:
sc stop "SysMain"
sc config "SysMain" start=disabled- Restart Windows
ℹ️ Note: Disabling SysMain is safe and does not damage Windows.
🔎 STEP 2: Disable Windows Search
Windows Search can constantly index files and push disk usage to 100%.
How to disable it:
- Open
services.msc - Find Windows Search
- Click Stop
- Set Startup type to Disabled
🚀 STEP 3: Disable Startup Apps
- Press Ctrl + Shift + Esc to open Task Manager
- Go to the Startup tab
- Disable apps that are not essential
🧠 STEP 4: Check Disk Health (SMART)
If your disk has physical problems, no tweak will permanently fix it.
- Use: CrystalDiskInfo
- If status shows Caution or Bad, the disk should be replaced
💽 STEP 5: HDD or SSD?
- If you are using an HDD, this issue is extremely common
- The best long-term solution: Upgrade to an SSD (huge performance boost)
✅ Summary (Proven Fix)
✔ Disable SysMain
✔ Disable Windows Search
✔ Disable Startup Apps
✔ Check disk health (SMART)
✔ Consider upgrading to an SSD
📌 This method actually works and is not a YouTube myth.
If the problem continues, there is a very high chance your hard drive is failing.
✍️ Guide prepared by Tips2Fix – real solutions, no fake tricks.
