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What does "Pri Master HDD Error" mean on boot?


When powering up my friend’s computer, it comes up “Pri Master HDD
Error”. Then it says to insert boot diskette in A. He is running
Windows XP. What does this mean?

It means that your friend’s computer has a problem.

The fact that it’s supposed to be running Windows XP is actually
beside the point … the computer hasn’t even gotten that far yet.


A cryptic message like “Pri Master HDD Error” means that the computer’s BIOS cannot access the hard disk (HDD: Hard Disk Drive) in the computer in order to boot. In fact, it apparently can’t even find the disk to even try to read anything from it.

Since it cannot boot from the hard disk, it’s asking you to insert a boot diskette into the floppy drive, typically referred to as “A:”. Even if you have no floppy drive the BIOS may still ask for it; it can’t boot, so it has to ask for something.

Unfortunately, the error message doesn’t really tell you anything specific about the actual error. It’s the computer’s equivalent of saying “something’s broken” without really telling you what that something is.

“If you’re not comfortable opening up your machine and poking around a little, this would be the time to take it to a technician for diagnosis.”

If you’re not comfortable opening up your machine and poking around a little, this would be the time to take it to a technician for diagnosis. As we’ll see in a moment, the problem could be any of several different issues, and they’ll need to see the machine to determine what it is.

In your shoes, the first thing I would do down “the try-it-yourself path” would be to turn off the machine, unplug it, wait a while, and then plug it back in and try again. I know it sounds either stupid or magical, depending on your point of view, but removing power for “a while” can often cause things that are electrically ‘stuck’ to sometimes reset themselves. If it works, which admittedly is not all that often in a case like this, it’s cheap and fast.

If that didn’t work, I’d once again turn off the machine and unplug it, because this time I’d be going inside. I’d open the computer (if it’s not a laptop, that is) and check the cabling, making sure that cables, both data and power, are securely seated and “pushed in” all the way. It’s not uncommon for a marginal connection to suddenly stop working without apparent cause or at the slightest bump. Once again, if it works it’s cheap and easy.

If you know enough to identify that your computer uses an add-on disk controller that sits in an expansion slot, I’d make sure that it, and all the expansion cards for that matter, were seated properly.

Similarly, I’d also be tempted to remove any expansion cards that weren’t absolutely necessary to boot the machine – sometimes a failure on one card can cause an error to appear as if it’s coming from another place.

Another good diagnostic step, once again with the power off, is to disconnect the hard drive, and then attempt a reboot just to see if there’s additional failure information that can be gleaned from the resulting error message.

At this point, things get tricky. My next step would be to connect the hard disk in another machine and see if it works at all. If it doesn’t, that’s a likely indicator that the hard disk itself has failed and needs replacing.

If the hard drive does work in a different machine, then the problem is likely with your disk controller or motherboard. I say “likely” because things are rarely that cut and dried. Hence this is, once again, where I’d be recommending a technician to confirm this before running out and replacing either.

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7 comments on “What does "Pri Master HDD Error" mean on boot?”

  1. Sometimes this error is caused by a faulty BIOS.
    You might want to try and flash your BIOS (check the pc’s manufacturer’s website on how to do that).

    Before putting your hard drive in another computer, I would try running the xp repair console from your installation disk (if you have one that is ;-).

    If you’re unfamiliar with all of the above, I would do as Leo says and take it to someone who knows what they’re doing!

    In any case, I hope yer friend has backed up all his data…

  2. This has happened to me a couple of times but by inserting the xp cd and bringing up the repair console and running the “fixmbr” command which rewrites the master boot record fixed it. Worth a try.

  3. I have an elderly Windows 98 SE machine which displays the message “Primary Hard Disk Fail” every ten or so times I boot it up. I just switch off, remove the power cable from the back of the machine and then insert it again a couple of times to discharge static. The machine then boots up normally!

    I hope you’re backing up. Someday what you’re doing won’t work, and it’s possible that all the data on that drive will be gone.

    – Leo
  4. There are a couple of other things that you might try to restore the machine. If you can, open the machine and remove the IDE cable that connects the hard drive to the mainboard at both ends. Do this several times for both ends of the cable; sometimes (especially on older machines) corrosion builds up in the connector(s) at either end of the cable which will cause erratic performance of a seemingly random nature. Removing the connector(s) and reinstalling them several times will remove any corrosion buildup. Another thing that you might try, especially in an older machine, is to replace the “keep-alive” battery on the mainboard! Most people forget that it’s there, and after about 3 – 5 years, it fails erratically. Its sole purpose is to keep information in the ROM intact – it’s not rechargeable, and if it’s not providing enough “juice” some or all of your ROM settings (including your hard drive specs) can get corrupted, which may give you the type of error message you’re seeing…Regardless, back up your data as soon as possible, because it could be a failing hard drive!

  5. I had this error message after fitting different hard drive and found I had the jumper set wrong on hard drive. Switched it to master and it is fine.

  6. This is a very common issue with the older Bios setup such as I have…Q-Lity Motherboard with:AMI Bios(American Megatrends). Here, try this: F1 to enter set up mode. Then enter boot path options:1-Enable,2- IDE-0,3-IDE-0,4-CD Rom,5-tryother?yes.Then: You need to enter your: Pri Master and Select Master(Pri-slave & Select-Slave) if: You have (2) Two Hard drives installed. You will need to research the MFG of the type of HDD installed for: Disk,Cyc,Mode,Head size ,etc. *If your only running one Hard drive..*.Pri Master=set values. *Select Master=Set values. *Not installed on: Pri-Slave, and, Select -Slave.Or…Set on Auto…all auto on. If it still doesn’t recognize or Locate them…you will need to reset your boot path options again (ie) Try: Enable, CD Rom, IDE-0, IDE-O, and , Try other. Sooner or later it will pick it up…but it takes time! Wish you the best.May the Lord help you!


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