What is USB Write Caching and how to disable it?

In this guide, we'll start by defining write caching and examine its potential advantages and disadvantages.
What is USB write caching and how to disable it

Table of Contents

In this guide, we’ll start by defining write caching and examine its potential advantages and disadvantages. Then we will show you how to enable or disable write caching on Windows10, Mac, and Linux operating systems as you wish.

  • Windows
  • Mac
  • Linux

The Definition of “Write”

In the context of a computer, a write is an act of retrieving information from a source and then directing that information to a destination. Often referred to as a write command, you can think of it as a paste function when you type and paste the text. All storage media and files are generally writable, but writing may be restricted depending on the administrator’s access rights.

The Definition of ”Caching”

Caching, on the other hand, is storing data in a cache or temporary storage space. Probably the most popular use of caching is in a web browser, where the data you request from a web page is stored in a cache folder on your hard drive. The next time you return to the same webpage, the browser will access the cache folder instead of sending another request and waiting for the server to retrieve the data. This will make your browsing experience faster.

The Definition of ”Write Caching”

Combine these two functions to form a write cache operation.

Write caching is the process of placing data in a cache in the system’s fast and volatile memory (RAM) before it is written to a destination. This process allows users to perform other tasks while waiting for their data to be written, with minimal impact on system performance.

This process is especially important to improve the performance of external drives such as USB flash drives. Thin, non-toxic storage devices may not be as fast as built-in drives, so writing many or large files to them often takes time.

Thanks to the write cache, however, you can wait without fingers. Your computer can store all of these written commands in its RAM and make them available separately to the flash drive when it’s ready.

You will see the progress bar reach 100% immediately and the dialog box will close quickly. However, note that the task is not fully complete. The actual writing continues to take place in the background, but the benefit is that you can perform other tasks while the computer transfers the cached content to the USB drive.

While this can be very beneficial, write caching has its drawbacks. The main disadvantage is the risk of data loss and corruption. If you accidentally disconnect the USB drive from your computer or turn it off while the writing process is still in progress, there is a high risk of losing the written data or corrupting files.

Although the implementation can be completely different, the principle of write caching is the same on all operating systems.

Write the cache On Windows

On Windows, write caching is disabled by default for USB drives, except for drives that use the NTFS format. The following guide will show you how to enable this feature in Windows 10 to improve USB drive performance.

  • Open File Explorer.
  • Right-click This PC.
  • Click “Manage”.
  • In the left pane of the Computer Management window, click Disk Management.
  • Find your USB drive in the middle. Usually hard disk 1. If you are still not sure, check the capacity of the hard disk. Please note that the actual volume shown is not exactly the capacity of the USB drive, so look for the capacity that is closest to the capacity of the USB drive.
  • Right-click on your USB drive and select Properties.
  • Click the “Policies” TAB.
  • Select ”Better Performance” and click ”OK”.
  • Close the computer management window, all is well!

To avoid data loss, be sure to click the small Safely Remove Hardware icon in the taskbar before disconnecting the USB drive. This tells the computer to stop writing the data to ensure all transferred files are intact.

Write the Cache on Linux and Mac

Unlike Windows, Linux and Mac operating systems enable write caching by default.

Some users prefer to disable this feature due to the risk of data loss or corruption. To do this, the command must be executed in the terminal. Here is a guide on how to disable write caching on Linux and Mac.

How to disable the Write Cache on Mac OS

  • Open the Applications folder, and then click Utilities.
  • Double-click Terminal.
  • In the Terminal window, run Mount.
  • Note the name of the USB drive.
  • In the terminal window, type umount /dev/disk1s1, where disk1s1 is the name of the USB drive.

How to disable the Write Cache on Linux

  • Press CTRL + ALT + T to start the terminal.
  • Run Sudo gedit /etc/hdparm.conf
  • Find write_cache and remove the # preceding it.
  • Save and restart your computer.
  • Write caching is a great performance enhancement, but it has its pros and cons. To be safe, always remember to safely eject a USB drive or external storage device before unplugging it.


DiskMFR Field Sales Manager - Leo

It’s Leo Zhi. He was born on August 1987. Major in Electronic Engineering & Business English, He is an Enthusiastic professional, a responsible person, and computer hardware & software literate. Proficient in NAND flash products for more than 10 years, critical thinking skills, outstanding leadership, excellent Teamwork, and interpersonal skills.  Understanding customer technical queries and issues, providing initial analysis and solutions. If you have any queries, Please feel free to let me know, Thanks

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