Reallocated NAND blocks high on MX300 275GB M2 SSD

Kilobyte Kid

Reallocated NAND blocks high on MX300 275GB M2 SSD

Hi, as the title states, the NAND block count has been rapidly climbing in the last few weeks by a rate of 4-5 per day which is worrying me. I've had this SSD since June of 2017 and its running firmware M0CR040. 8.22 TB have been written on it so far and theres 160/275GB free space. Anu idea what's going on? Is the drive failing? I know thelifetime is 96% but aren't these extra blocks supposed to replace the faulty ones? At this rate they'll run out in no time.  Thank you.Screenshot (119).png

5 Replies

Re: Reallocated NAND blocks high on MX300 275GB M2 SSD

You need to update the firmware to M0CR060 as I've experienced issues with the older firmware not properly reallocating bad blocks.  I don't know if it will have any effect in your situation though, but it cannot hurt.   While the firmware update is not supposed to destroy data, you should make sure to backup anything important first just in case.


If the bad blocks and errors continue after the firmware update, I would suggest performing a Secure Erase on the SSD and then filling the whole drive a couple of times to see if you can force the rest of the bad blocks to be found and reallocated.  Then perform another Secure Erase to reset the drive to factory defaults and performance before restoring your OS.  You might be able to install the Acronis software again and create a bootable USB drive and clone your current  installation to an image file on another larger drive.  Once your tests are done, then clone it back.  Or it might be possible to have Windows create a bootable backup image to do the same thing.  I'm not sure if the Crucial version of Acronis will allow this and I don't know how the Windows' option behaves or if there are any disadvantages.


While filling the drive several times will wear the drive a bit I believe it is worth it to find out if the bad blocks & errors will stop accumulating.  If the problems continue your SSD is still under warranty.


You may also want to run a basic chkdsk scan on the SSD to see if the filesystem has accumulated any errors from these bad blocks.  Don't run the bad block scan on the SSD.  You will want to uninstall Acronis after using it since some people have experienced issues with it installed.


Kilobyte Kid

Re: Reallocated NAND blocks high on MX300 275GB M2 SSD

Hi, I've updated the SSD firmware since your post and so far everything seems fine for the time being. Hopefully it stays that way. Thank you.

Crucial Employee

Re: Reallocated NAND blocks high on MX300 275GB M2 SSD

@hemingway60 I would also suggest you adjust these power settings. You have basically three power cycles every hour of use and while not necessary bad for a drive, could contribute to higher reallocation count. And as a general rule of thumb it's a good idea to not cycle power an SSD unless it's necessary. SSDs unlike HDDs have virtually no power consumption when in standby so there isn't much benefit to having power cut to them.

- Go to Control Panel
- Go to Hardware and Sound
- Go to Power Options
- Select Change Plan Settings
- Select Change Advanced Settings
- Make sure the 'hard disk' field is set to ‘never’ (Laptop users select 'battery and power adapter').

Crucial_Benny, Micron CPG Support, US

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Kilobyte Kid

Re: Reallocated NAND blocks high on MX300 275GB M2 SSD





Re: Reallocated NAND blocks high on MX300 275GB M2 SSD

You could try letting your system sit idle at the BIOS screen or the BIOS boot menu screen overnight.  It might allow the SSD's internal controller to have time to do some internal maintenance.  If the errors still increase afterwards, then you should try my earlier suggestion about a Secure Erase.   The second paragraph of that post also mentions filling the drive a couple of times to force a write to as many blocks as possible hopefully triggering any failing ones to reallocate.  The Secure Erase actually affects every block on the SSD so maybe it will realize some other blocks are bad and reallocate them for you.  Or perhaps the earlier firmware left the SSD in a wierd state which the Secure Erase should fix since it resets the SSD to factory defaults.  I had to do this to all of my MX300s to resolve my issues left over from the earlier firmware.  If they don't stop failing, then I would RMA the drive since this is the most you can do to solve the problems.