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SSD 535 240GB not enumerated by BIOS or shown as sandforce

New Contributor


my SSDSC2BW240H601 was working fine for almost a year in a mostly idle Ubuntu 16.04 system. Recently it started misbehaving:

For no apparent reason it would just disappear and on subsequent system restart BIOS will fail to enumerate device or it will be presented as sandforce.

Sometimes it does manage to initialize correctly and by looking at the report from Intel's SSD Toolbox it's health status is OK, and as far as I can tell it is running latest firmware - RG21.

Any ideas?


Esteemed Contributor III

Hi nadrimajstor,

We understand your situation regarding your Intel® SSD 535 Series.Based on the information provided, it seems that the controller inside of your SSD may be failing. In order to better address this problem we can recommend for you to contact your local support team to verify the warranty information for your drive, which may need to be replaced.Regards,Junior M.

New Contributor II

Here's a link to another thread with the fix.


I've got hundreds of these drives deployed in various desktop computer models, and randomly after 1+ years of operation they start encountering this problem. The firmware that disables DevSleep does seem to fix it. I've never gotten an explanation why the drives work fine for over a year and then start encountering this issue.

Esteemed Contributor III

Hi citybett,

Thanks for the information provided. We would like to let you know that this could be related to the write amplification. Here is the definition of it: Write amplification is the difference between host writes and NAND writes. There has been concern over the amount of write amplification while using the Intel® SSD 530 Series and the Intel® SSD 535 Series. Some users have noted that the write amplification on the Intel® SSD 520 Series was much lower.The Intel® SSD 530 Series and Intel® SSD 535 Series added architectural changes around power savings with low-power states, which changed the drive behavior compared to predecessors in this same product line. Low-power state support requires the drive to perform bookkeeping activity in the background for data loss protection and faster resume from low-power states. This adds a factor to the write amplification. For example, a small quantity of host writes accompanied by low-power state transition, the write amplification will be due to the writes performed by the background bookkeeping plus the host writes. On some systems, this may have write amplification impacts. However, the drive was also built to meet the same reliability and endurance standards as the Intel® SSD 520 Series.Some write amplification are expected. Because of the NAND architecture, while other drive activity is occurring, the drive performs garbage collection by moving "in use" data to new areas and reclaiming deleted blocks as free space. The amount of write amplification depends on the type of writes and amount of deleted data. Certain workloads can trigger a higher write amplification. For example, small file size write operations over long periods of time can generate more garbage collection than large file size write operations.The power saving modes in the Intel® SSD 530 Series and Intel® SSD 535 Series products can also add extra background write operations before taking the drive into a lower power state. If the drive transitions into lower power and then wakes up often, the number of background operations can increase. In effect, write amplification increases. Standard user activity is typically a mix of write behavior (not only small IOs) with power-saving transitions spread out over time.If your typical activity is not approaching the endurance rating as specified in the product specification, there should be no excessive wear out on the Intel® SSD. If you have any concern about wear out, monitor the SMART attribute E9h. We warranty the Intel SSD based on your adherence to usage as stated in the product specification.High write amplification is typically observed when there are fewer host writes and/or the drive goes through many idle cycles with no host activity. Bookkeeping tasks to preserve the drive's state during idle time result in a higher write amplification.We have introduced a solution that addresses the high write amplification concern of some customers. You may see some impact to battery life based on usage behavior. Intel technologies' features and benefits depend on system configuration and may require enabled hardware, software, or service activation. Performance varies depending on system configuration. No computer system can be absolutely secure. Check with your system manufacturer or retailer or learn more.Intel disclaims all express and implied warranties, including without limitation, implied warranties of merchantability, fitness for a particular purpose, non-infringement, and any warranty arising from course of performance, course of dealing, or usage in trade.Intel, Intel® SSD 520, Intel® SSD 530, Intel® SSD 535 Series, and the Intel logo are trademarks of Intel Corporation or its subsidiaries in the U.S. and/or other countries.You can download the fix it here. Please let us know if there is something else we can assist you with. Regards, Junior M.

New Contributor

It is possible that the issue with your SSD is related to the firmware. Since you say that it is running the latest firmware, RG21, it is unlikely that this is the cause of the misbehavior. It is possible that your drive is suffering from a hardware-related issue, and it might be best to run a diagnostic check to see if there are any errors. You could use a tool such as HD Tune to get a better idea of the health status of the drive. Additionally, you could use a tool such as CrystalDiskInfo to check the SMART attributes of the drive, which might give you more information about the cause of the problem. If none of the above tools indicate any issue with the drive, it might be a good idea to run a low level format on it, to see if that resolves the issue.

Give information about bookkeeping or do what is asked of you regarding bookkeeping.