If your mechanical hard drive is constantly running at 100% disk usage on Windows 10 or 11, it can be due to several reasons:

1. Background Processes and Services:

• Windows might be running various background processes and services that are utilizing the disk, such as Windows Search Indexing, Windows Defender scans, system updates, and other maintenance tasks.

1. Malware or Antivirus Scans:

• Malware or antivirus scans can significantly increase disk usage, especially if they are set to run regularly or on a schedule.

1. Insufficient RAM:

• If your system lacks enough RAM, Windows may use the hard drive as virtual memory (paging file), which can lead to high disk activity.

1. Faulty Hardware or Drivers:

• A malfunctioning hard drive or outdated/incompatible drivers can lead to increased disk activity.

1. Software or Applications:

• Certain applications or software can have bugs or issues that cause them to excessively use the disk.

1. File System Errors:

• File system errors or disk fragmentation can lead to increased disk activity as the system tries to read or write data.

1. Windows Update:

• Windows updates can cause high disk usage, particularly during the download and installation process.

1. Superfetch/Prefetch:

• These are Windows features designed to improve system performance by predicting which applications you'll use and preloading them into RAM. However, they can sometimes contribute to high disk usage.

1. Power Management Settings:

• Some power management settings may cause the hard drive to work more than necessary, such as aggressive power saving options.

1. Third-Party Software Interference:
   • Certain third-party software, especially background utilities or utilities that interact with the file system, can lead to high disk usage.

To resolve the issue, you can try the following steps:

1. Check for Malware:

• Perform a thorough scan using a reputable antivirus or anti-malware program to ensure your system is clean.

1. Update Drivers:

• Make sure all your drivers, especially for the hard drive and storage controllers, are up-to-date.

1. Check for Windows Updates:

• Ensure that your system is fully updated to the latest version.

1. Disable or Adjust Services:

• You can selectively disable or adjust certain Windows services that might be causing excessive disk activity.

1. Increase RAM:

• If possible, consider upgrading your RAM to reduce reliance on virtual memory.

1. Check for Disk Errors:

• Run a disk check utility to look for and repair any file system or disk errors.

1. Monitor Task Manager:

• Use the Task Manager to identify which processes are using the disk the most, which may give you a clue about the root cause.

If the issue persists, you might want to seek further assistance from a computer technician, as it could be related to specific hardware or software configurations on your system.