Troubleshooting A Faulty SATA Port

One of the most frustrating things in computer repair is an intermittent (seemingly random) fault. It can suck up a lot of diagnosis time and, unless you can pin down the problem, it is difficult to be sure if any ‘repair’ has actually worked or if you just got lucky and the intermittent problem will return in a few days…

A perfect example is an issue we saw recently which turned out to be caused by a faulty SATA port on the motherboard. We will explain how we arrived at the solution – it reinforces the need to have a logical approach to diagnosis yet not to become so blinded by the ‘most common’ causes that you fail to consider much rarer alternatives.

Reported Problem – 4 year old Vista PC working fine most of the time but suffering occasional blue screen of death (BSOD) crashes or long freezes followed by automatic shut down and restart. The issues had been getting worse for 6 months and now averaged about once a day – but with no pattern as to how long the PC was on for or what software was in use at the time…

These types of error can be caused by either a hardware or a software problem – and, being intermittent, are not easy to diagnose so a thorough investigation is needed.

Steps To Diagnose The Problem – We first backed up all the important documents before attempting any diagnosis! This is really important if hardware failure is suspected e.g. if a hard drive is dying then testing it might just finish it off. Always play safe and ensure you have a full backup before continuing with diagnosis.

1.  We checked Event Viewer, looking particularly at the System logs for relevant errors. Several errors typically related to memory (RAM) faults so we tested the memory – no faults found. (If the problem were not so intermittent we could have just swapped out the RAM to test it)

2.  Other errors were typically related to hard drive faults – although they may have been caused by the frequent unexpected shutdowns corrupting the Windows file system. As the PC was 4 years old we tested the hard drive to check if it was failing – no faults found.

3.  A faulty PSU (Power Supply Unit) could cause random freezing and restarts so we tested it under full load – no faults found.

4.  Overheating could also cause these issues so we stress tested the PC – no faults found. We also tested the temperatures of the main components using Speccy – all within normal limits. Grrr :-(

Next Steps – So far we had established that the hard drive, RAM, PSU and temperatures were all fine – there were no other separate components (like a graphics/sound card) so this narrowed down the cause to an intermittent motherboard problem or software errors.

The biggest issue was not being able to reproduce the error – even under stress testing the PC had remained resolutely stable for us with no crashes or freezing. Unless we could find a ‘smoking gun’ we could not justify wasting a lot of time updating drivers/software willy nilly, and certainly not wasting a lot of money replacing the motherboard or writing off the PC – we needed to make this PC crash.

  • Considering all the information to date, our instinct and experience still pointed us towards an issue with heavy file read/write access causing related memory and hard drive issues, hence the crashes/freezing…
  • So we ran a full virus scan on the PC (also useful to rule out virus activity) which would read/check every file but found no issues – and still no crash.
  • Next we decided to do a disk cleanup – lo and behold it froze half way through and the PC shut down!
  • To make sure, we tried a few disk cleanups in both normal and safe mode and the PC froze up every time. At last we could reproduce the problem at will so could proceed with diagnosis and repair, confident that we could test for sure if we had been successful.
  • To test for motherboard issues we changed the hard drive SATA data cable – disk cleanup still crashed. We then moved the hard drive SATA data cable to a different SATA port on the motherboard – and disk cleanup finished successfully :-)

We repeated the test by trying a few disk cleanups in both normal and safe mode and they were successful every time – no freezes at all. As a final check, we moved the SATA cable back to the original port on the motherboard and, sure enough, the disk cleanup started failing again – proving for sure that particular SATA port was at fault.

Updated 29th Dec 2012 – some readers have asked what to do if you find that all your motherboard SATA ports are faulty (especially if you only have 2). Possible solutions would include:

1. Add more internal SATA ports by adding a SATA PCIe card (if you have a free PCIe slot) or a SATA PCI card (not as quick but will do the job) – note that you  may have to play around with loading SATA drivers when installing Windows.

2. Use an IDE port instead if you have an IDE hard drive available.

3. Buy a new motherboard.

4. Even if you decide to buy another PC, as long as the SATA hard drive itself is not faulty, you could reuse it in a new PC or just retrieve your personal data from it (by attaching it temporarily in another PC).


The original SATA port (or associated disk controller) on the motherboard was faulty – but only intermittently and under heavy disk activity. This is a very rare outcome – the usual sign of a faulty SATA port is that the hard drive is not recognized in BIOS or Windows does not load, producing a disk read error or ‘no operating system found’ message.

It underlines the importance of thorough step by step testing and being able to reproduce a fault so that you can test if a potential fix actually works – otherwise you’re just shooting in the dark.

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13 Responses to: "Troubleshooting A Faulty SATA Port"

  1. pb says:

    “One of the most frustrating things in computer repair is an intermittent (seemingly random) fault.”

    Just figured this out on a HP Z420 that has to use two disks- one for RHEL system, one for /home to run proprietary software. Seemingly random instances of ‘read error’, ‘no system files on disk’…… but disk would pass the tests. Once it booted it would run fine but booting was wildly problematic. Fortunately the Z420 has a bunch of SATA ports and moving to another port seemed to have fixed it. Many hours of frustration looking through BIOS & Grub.

  2. TFDerrick says:

    RE: “Freezing the hard drive” this was once suggested to me by a friend who had spent many years working at Hewlett Packard – this suggestion is for older drives – something to do with loose bearings (?) – I recently used this process to save the data from an old Seagate (ST31000340AS) that had gone south.

    • Roy says:

      @TFDerrick – cool (literally!), nice to know that saved the day :-)

      For anyone else, it is best used as a (very) last resort if all else fails and can only help in specific circumstances – e.g. where the drive rapidly overheats due to wear/failure so freezing it can hold the temperature down long enough to recover data.

  3. surya says:

    I have the same problem,i got a new sata hard disk,but in my case even if i use any of the 2 sata ports i wont be able to boot.( along with tickling sounds from hard disk). and get the DISK READ ERROR.. i tried to load the operating system using the IDE PORT through other hard drive and it was successful..!! is there any way to solve the sata inerface problem?

    • Roy says:

      @Surya – ticking/clicking sounds from drive sounds like a dead hard drive – it’s known as the ‘click of death’. Are you 100% certain it’s not the drive which is faulty – even a new one can be faulty? Test it on another PC as it sounds like a problem with the drive, not the ports.

      However, if SATA drive is definitely ok but both SATA ports on the motherboard are faulty then you can either 1. buy a PCI Express SATA card to add new SATA ports (if you have a spare PCIx socket else a PCI SATA card) 2. use IDE instead or 3. buy new motherboard

  4. Mike says:

    As Alfred says, “Why didn’t I come across this article…”. Luckily all I did was throw away a probably perfectly good SATA cable. My PC had the symptoms as mentioned in the conclusion. The hard drive was intermittently not recognized in BIOS or Windows does not load, producing a disk read error or ‘no operating system found’ message. The computer has two hard drives and only two SATA ports so what to do? I purchased a cheap PCIe SATA card and thanks to Jmicron all now well again without the expense of a new motherboard. :)

  5. Alfred says:

    Grr.. Why didn’t i come across this article before going out and purchasing a new power supply..

  6. Leonardo and Iago says:

    Today we had this issue and we could reach the same conclusion. At least we could indentify two SATA ports that allow the system to work. Not sure for how many time more…

    • Roy says:

      In some cases the new port works ok for years but in other cases it may also fail within a few weeks/months – depends on how/where the motherboard is at fault.

      Hope you’re lucky and the new ports stay ok – do keep a good full backup just in case

      • Leonardo and Iago says:

        Until the new pc arrives we are working with 2 HD’s , after, this motherboard will be retired.
        It is a GA-H67MA-UD2H, 1.5 years old only.
        Thank you,
        Our best regards from Brazil.

  7. Mike Thomas says:

    I have the same problem, but I interchange my connections to the motherboard each time and BINGO…It works. I reuse the 4 SATA ports continuously each time.
    It’s not a regular occurence, but it does often happen. The ports are not faulty, the hard drive just doesn’t jive with the moterboard sometimes……I’m guessing.

    • Roy says:

      That’s odd, if you reuse all the sata ports it suggests none of them are at fault – I would certainly change your SATA cable in case the end connecting to the mobo isn’t a great fit and works slightly loose over time (then is ok when pushed in firmly on another SATA port – for a while)

      SATA connectors are a poor design as the plastic end expands/softens over time to produce a bad connection – for that reason there is a limit on the number of times you can plug it in too, I think it’s about 50? I’ve had to replace several that looked ok but didn’t actually plug in firmly enough, leading to intermittent disk errors.