How can I reset the SMART results so it does not register previous results. My reason is that I was testing the hard drives closed together on a closed case. This made one of the HDD fail the Airflow Temperature reading.

After opening the case up (Which lowered the Temp of all drives 10 degrees Celsius in 5 minutes) and then separating the drives a bit more (3 less degrees) All results were good but since the Airflow reading failed in a previous reading, it always shows as failing.

So how can I reset the readings for SMART?

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  • 1
    I think you can use Mhdd to turn off smart, It's with the floppy tools on sysresccd.org/System-tools not the best idea... but might be worth looking into.
    – Mateo
    Sep 8, 2013 at 17:31
  • 2
    Why do you want to reset it?
    – Angelo
    May 12, 2016 at 18:43
  • Well it was basically 3 years ago, but I reckon it was because, at that moment, the HDD was on a place that had A LOT of external heat. After moving it to a room with more of a cold climate, the issue still persisted, although the temperature went from 68 degrees to 37 degrees. So the issue was an external temperature rise that created the issue in the beginning but was still showing after moving it to another place. May 12, 2016 at 20:09
  • @LuisAlvarado unfortunately your reply is totally wrong. SMART reallocated sectors count has nothing to do with G-List (firmware specific) in drives. G-List is the reallocation map of hard drives and every manufacturer has its own G-List format. SMART reallocated sectors and even worse pending sectors are simply the buffer that makes the SMART predictive failure to work. In fact it makes no difference that you have a (roughly) 1 billion sectors 500GB hdd or a 4 billions sectors 2TB, the SMART reallocation table has only 200 or 250 sectors. Robert CTO @ RecuperoDati299euro.it
    – Robert
    Jul 5, 2020 at 7:54
  • Thank you @recuperoDati for the clarification. Now I know more about SMART. Jul 6, 2020 at 12:21

7 Answers 7


Actually there is a way to reset S.M.A.R.T. data. You only need simple rs232 to usb converter (uart to ttl) and a few cables attached to hdds diagnostic interfaces. (it's on the right side of sata port, 5 or 4 pins) You must conect RX TX and GND cables (and power cable of course :D) then power on HDD and connect to it with putty or hyperterminal (linux can connect with it's own terminal i guess) for example for seagate drives: for 7200.10 and older baud rate is 9600 for 7200.11 and newer is 38400

commands after connection hit CTRL + Z then type "/1" hit enter type "N1" hit enter when it finishes remove all cables and turn on HDD like normal to see changes :)

for other hdd info use google :)

  • 7
    This only seems to apply to Seagate drives but you are right, this video explains the process. Feb 24, 2016 at 11:28
  • 5
    One of my coworkers contacted Seagate, and they told us they've since locked this feature down so it cannot be accessed without a proprietary tool. Not sure at what point they did this.
    – jfa
    Dec 8, 2017 at 1:30

The point of current / worst attributes like temperature is exactly this: to tell you if the drive has ever been outside its max operating temperature, and thus might have suffered permanent damage.

That's why it says "failed in the past", not "failing now": you did just barely touch the max-temp threshold. Note the attribute display shows "normalized: 50, threshold: 45, worst: 45". (These are 0..200 normalized values like for any other attribute, not raw Celsius temps.)

You also have some bad sectors (uncorrectable sector errors), so whether the brief high temperature caused that or not, it's probably time to ditch that drive.

A better SMART software UI would show you the current and max-ever temp. e.g.
smartctl -a /dev/sda or smartctl -x /dev/sda (-x prints all available SMART and non-SMART data it can get from the drive, including a temperature history log if the drive has one, with an ASCII bar graph.)

smartctl -x includes this for an old WD Green 1TB (WD10EADS) hard drive:

Current Temperature:                    36 Celsius
Power Cycle Min/Max Temperature:     25/42 Celsius
Lifetime    Min/Max Temperature:     35/46 Celsius

The software you're using looks like it's only showing the current temp, which is slightly below the threshold, but it's not going to hide the fact that the drive was out-of-spec at some point in the past.

You could certainly justify ignoring that momentary high-temperature, if you really did correct it in minutes. But you won't (or shouldn't) ever be able to make the drive itself lie about the fact that it was over its rated max temp for some time, and thus the attribute did fail in the past.

You can configure smartd to ignore any given attribute so you can still get a useful notification if anything else crosses a threshold into officially-failing territory.: smartd.conf(5) says:

-i ID [ATA only] Ignore device Attribute number ID when checking for failure of Usage Attributes. ID must be a decimal integer in the range from 1 to 255. This Directive modifies the behavior of the '-f' Directive and has no effect without it.

This is useful, for example, if you have a very old disk and don't want to keep getting messages about the hours-on-lifetime Attribute (usually Attribute 9) failing. This Directive may appear multiple times for a single device, if you want to ignore multiple Attributes.

Extended temperature-history attributes

I just got a new 6TB Seagate Barracuda (ST6000DM003-2CY186 firmware 0001, a 5425 RPM drive), which has some interesting stats, including time spent exceeding min/max operating points, and high/low of short-term and log-term temps.

SCT Status Version:                  3
SCT Version (vendor specific):       522 (0x020a)
Device State:                        Active (0)
Current Temperature:                    33 Celsius
Power Cycle Min/Max Temperature:     27/33 Celsius
Lifetime    Min/Max Temperature:     27/33 Celsius
Under/Over Temperature Limit Count:   0/0

SCT Temperature History Version:     2
Temperature Sampling Period:         3 minutes
Temperature Logging Interval:        59 minutes
Min/Max recommended Temperature:     14/55 Celsius
Min/Max Temperature Limit:           10/60 Celsius
Temperature History Size (Index):    128 (2)

And in the full-detail section:

0x05  =====  =               =  ===  == Temperature Statistics (rev 1) ==
0x05  0x008  1              33  ---  Current Temperature
0x05  0x010  1               -  ---  Average Short Term Temperature
0x05  0x018  1               -  ---  Average Long Term Temperature
0x05  0x020  1              33  ---  Highest Temperature
0x05  0x028  1              30  ---  Lowest Temperature
0x05  0x030  1               -  ---  Highest Average Short Term Temperature
0x05  0x038  1               -  ---  Lowest Average Short Term Temperature
0x05  0x040  1               -  ---  Highest Average Long Term Temperature
0x05  0x048  1               -  ---  Lowest Average Long Term Temperature
0x05  0x050  4               0  ---  Time in Over-Temperature
0x05  0x058  1              55  ---  Specified Maximum Operating Temperature
0x05  0x060  4               0  ---  Time in Under-Temperature
0x05  0x068  1              13  ---  Specified Minimum Operating Temperature

(The drive has only been powered on for a couple minutes; that's presumably why there's a - for no data in some of the fields.)

If you drive has these extended attributes, you can show someone that the time spent outside of allowed temp was very short (if that's the case). Presumably if you were going to modify the SMART data, you'd just have done that and removed any mention of it being out-of-range ever, but obviously you can't 100% trust any data from a 2nd-hand drive that someone's trying to sell you.

See https://superuser.com/questions/1389522/what-does-it-mean-when-my-new-hdd-reports-errors-at-a-time-that-shouldnt-exist for more about used drives with "odometer rollback" on their "Power_On_Hours" attribute for example.

  • Thank you Peter for the thorough analysis here. Greatly appreciated. Jan 2, 2019 at 16:15

SMART data is not very standard between manufacturers, but the Hard Drive Temperature test should indicate if the drive's temperature has gone over a threshold in the past: http://en.wikipedia.org/wiki/S.M.A.R.T.#Known_ATA_S.M.A.R.T._attributes

The thinking is that an overheat increases your chances for failure. SMART isn't saying your drive is bad, but has an increased chance for failure in the future.

SMART is meant to be an audit of the drives history and is maintained by the drive itself, so you cannot "reset" or "clear" SMART values.


A stupid thing about SMART is that it permanently stores one time transient things that did no damage at all. I had a drive that recorded a power failure in its SMART and forever after the computer would warn about the SMART data indicating "impending drive failure" simply because of a power outage caused by someone driving into a power pole. No idea why that specific power failure got recorded by SMART when I've had many computers and many drives experience power failures without recording them as an "error".

I had another drive I picked up used that had a SMART record of very briefly exceeding max temp by one degree thousands of runtime hours previously.

If SMART was really "SMART" it would not allow such transient "errors" to trigger the BIOS warning or OS X's refusal to install on drives that have any SMART "errors" at all recorded.

If there's real damage to a drive, it should quickly show up again in SMART after being cleared, just like problems do in vehicles with OBD2 and CAN systems.


Hard drives have spare space for recovery reasons. The recovery happens automatically. Recovery tools only remap physically bad sectors to this spare space. Once remapped, when a read or write occur to a bad sector, the drive turns the access to the spare space, and hides the error.

To be honest I don't know of a way to reset SMART data. It's something that the hard drive maintains internally, and in any event it would be a bad thing to do.

SMART reports that your hard drive is failing! Resetting the counters will not change the fact that an error threshold for the drive has been exceeded.

So NO, you can't Reset S.M.A.R.T. history. It's installed at the factory for drive evaluation upon failure. SMART can only be disabled or enabled.

I hope this answers your question.

  • 1
    Hi Mitch, well as explained in the question, the failure is not real. It was because all HDD were put very closed together on a poor ventilated space. After changing that and testing again it was working perfectly except that it was still mentioning the past failure. For the moment I did the following sudo smartctl -l sataphy,reset /dev/sdd which solved the issue of Overall Assesment taking the previous failure into consideration which now appears normal, but the failure still appears for the specific attribute. Again, the HDD is actually not failing but the previous error still shows. Sep 8, 2013 at 17:09
  • I understand, but it may appear normal, its only hidden. You asked if that can be reset, and the answer is NO. Even though you were able to hide the error, once the drive goes to the manufacturer for any reason, they can find out what actually went wrong with the drive over time. All I'm saying that the previous error still shows, and unless you can get your hands on tools used by manufactures, to rest the drive's SMART status, it will still show.
    – Mitch
    Sep 8, 2013 at 17:52


With specific Data Recovery machinery like Acelab, Atola, DFL, MRT, you can reset SMART tables and logs.

No sense in doing that though,

unless you aren't doing some low level data recovery task which does require this reset.

Resetting SMARTs is like think to remove the cast in the leg of a leg broken two days ago. You repaired nothing ... you simply hide a HUGE problem.

The leg is still broken and "using it" will cause pain and further additional damages ... exactly like loosing forever your precious data

HDDs with any kind of bad SMART, including temperature, are drives which

  1. are seriously in trouble
  2. have worked in really worse conditions

in either the cases you are simply trying to kill yourself data leaving them on such problematic drive.

SMART as the acronym says, is the self monitoring system of the self drive healthiness.

One day it tells you the drive is going to die. The job is done, the drive should (must) be replaced.

At that point you have a blinking ringing HUGE WARNING ... now what? It is in your decisions.


as written in a comment I have written in this thread,

SMART reallocated sectors count has nothing to do with G-List (firmware specific) in drives.

G-List is the reallocation map of hard drives and every manufacturer has its own G-List format.

It is a built-in mechanism in the drive's firmware, when a remap in the G-List happen, this is REGISTERED in the SMART table for reallocation counts.

SMART reallocated sectors and even worse pending sectors are simply registered in the SMART tables, they are simply part of the mechanism that makes the SMART predictive failure to work.

Note: It works as warning in the BIOS at boot or only if you have a daemon or a utility that do monitor the SMART status and warns you of eventual issues.

In fact it makes no difference that you have a (roughly) 1 billion sectors 500GB hdd or a 4 billions sectors 2TB, the SMART reallocation table has only 200 or 250 sectors.

... 200/250 , sometime 100, aren't they too few for so many billions of LBAs ?

So I would make a modification to the accepted reply since it makes to think that you can repair a failed drive ... the drive is FAILED you CAN'T FIX IT ,


you must take the SMART warning for what it is ... and replace the drive

Many of the unrecoverable drives that we receive, have been KILLED by such utilities mostly for the simple reason that a failing drive, needing to be kept TURNED OFF, has been massacred by an absolutely USELESS repair (killing) process


To my knowledge, the only way to stop it is to turn off SMART in the BIOS. This will only stop the HARDWARE, though.

Your OS will still query the drive for its SMART info and tell you it's failing.

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