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Why Is My SSD So Slow After the Windows 11 24H2 Update?
Your computer’s storage drive may be failing or running very slowly after a recent Windows 11 update. There is a reason for this, and it might not be what you think. The problem likely is not with the Windows update itself, but with a small number of storage drives that were sold with unfinished test software.
A Confusing Problem for Users
Many people were worried after installing a new Windows 11 update called KB5063878. They reported serious issues with their computers. For some, their fast NVMe solid-state drives (SSDs) seemed to disappear from the system entirely. The computer could no longer see the drive where all their files were stored. For others, their computers became incredibly slow and difficult to use. These problems started right after the update was installed, which made it seem like the update was the cause.
Initially, Microsoft, the company that makes Windows, and Phison, a company that makes key parts for many SSDs, investigated the reports. After their tests, they both announced that the Windows update was not connected to the drive failures. Phison stated that their own testing, which lasted over 4,500 hours, showed no problems between the update and their drive components. This left many users confused and without a clear answer.
Finding the Real Cause
New information has provided a much clearer explanation. A technology group on Facebook named PCDIY! discovered that the Windows update was not the direct cause of the failures. Instead, the issue seems to come from pre-release engineering firmware that was present on certain SSDs.
Firmware is the essential software that is permanently stored on your SSD. It acts like the drive’s brain, controlling how it reads, writes, and manages data. Engineering firmware is a very early, unfinished version of this software. It is used by engineers inside the factory for testing and development purposes. This type of firmware is not meant for the public because it can be unstable and have bugs. It appears that a number of SSDs were accidentally shipped to consumers with this unfinished engineering firmware still on them. The Windows 11 update seems to have triggered a hidden bug within this specific test firmware, causing the drives to fail or slow down.
The experts at the PCDIY! group shared their findings, which were later confirmed by Phison engineers in their own labs. The drives that were crashing were indeed using these pre-release versions of the firmware.
Who Needs to Be Concerned?
If you bought your SSD from a normal retail store, you probably do not need to worry. SSDs sold to the public are supposed to go through a mass-production process that installs the final, official firmware.
- Official firmware is thoroughly tested and verified to be stable and reliable. It does not have the same strange bugs that can appear in engineering firmware.
- The problem is limited to a small number of drives that somehow left the factory with the wrong software installed.
- Therefore, the vast majority of users with Phison-based SSDs will not experience this issue.
If you are experiencing drive failures or freezes after the update, the first and most important step is to back up all of your data immediately. Save your important documents, photos, and other files to an external hard drive, a different computer, or a cloud storage service like Google Drive or OneDrive.
After your data is safe, you should check the website of your SSD’s manufacturer for a firmware update. Companies like Samsung, Crucial, Kingston, and others provide tools to update your drive’s software. Installing the latest official firmware can replace the buggy engineering version and fix the instability.
Understanding Sudden Slowdowns
Phison also clarified a separate issue that some users reported: severe slowdowns during large file transfers. This particular problem is not a bug and is not directly related to the Windows update. It happens when a part of the SSD called the SLC cache becomes full.
Most modern SSDs use this SLC cache as a small, extremely fast temporary storage area. When you save a file, it goes to this fast cache first, which makes your computer feel very responsive. If you are moving a very large file, like a movie, this small cache can fill up. Once it is full, the SSD has to start writing directly to its main, slower storage sections. This change causes the transfer speed to drop suddenly, and your computer will feel slow until the transfer is finished.
The fix for a constantly slow drive due to a full SLC cache is a process called a Secure Erase. Simply formatting the drive in Windows will not clear the cache properly. A Secure Erase is a special function that wipes the drive completely and resets it to its original factory state. This process will delete everything on the drive, which is why having a backup of your data is critical. You can usually perform a Secure Erase using a software utility provided by your SSD’s manufacturer.