Convert an Old Hard Drive into an External Unit


It’s quite common to have an old computer die on you and not have it repaired, especially if it’s more than a few years old. But what can you do with the old carcass? 

If a computer dies for any reason other than a dead hard drive, you can always convert the old drive into an external unit, and grab important files off the drive in the process. The same thing can be done if you install a larger hard drive in your computer and don’t know what to do with the old one.

The first thing you should do before investing any time and money in an old hard drive is to try to determine if it’s ok. If your old computer was working fine and then died all of a sudden, the hard drive is most likely fine. Motherboards, power supplies, microprocessors and memory can fail in the blink of an eye, but hard drives usually become flaky, make strange sounds or exhibit other errors before they die. If your hard drive seemed fine before the system died then it’s probably OK.

Likewise, if your system was working fine and you simply swapped the old hard drive for a bigger one, then the old one should still be just fine. We won’t get into the details of upgrading a hard drive because it’s a very complicated process. But the easiest way to upgrade is to use hard drive cloning software or hardware that lets you duplicate your original hard drive on a much bigger, blank hard drive. Once duplicated, you simply swap out the old drive for the new one. Otherwise, you can simply install a new hard drive in your computer and format it from scratch. Of course, you’ll need the discs for the operating system, all the drivers and utilities and all of your applications, along with the corresponding serial numbers where required.

Getting back to creating an external hard drive, the next thing you need to make certain of is the size and type of drive you have. Notebook computers typically use 2.5-inch hard drives, simply because they’re smaller and use less power than 3.5-inch desktop hard drives. If you’re not sure what size your drive is you can measure it. Hard drives have a rectangular shape, and the smaller of the two sides is where the size is measured.


Next, you have to determine what kind of drive you have because you need an enclosure that’s compatible with your drive. Older computers contain PATA, or IDE hard drives, and newer ones contain SATA hard drives. The connectors on PATA hard drives consist of a double row of metal pins, while the connectors on SATA hard drives consist of two flat tabs.

You need to buy a hard-drive enclosure that matches the size of the drive you have; a 2.5-inch enclosure for a 2.5-inch drive and a 3.5-inch enclosure for a 3.5-inch drive. Keep in mind that 2.5-inch enclosures are usually bus powered, meaning that they pull power from the port they’re plugged into and they don’t come with a power adapter; this makes them completely portable. On the other hand, 3.5-inch hard drives need more power than can be pulled from a computer port, so the 3.5-inch enclosures usually come with an AC power adapter and they are not portable—meaning that they won’t work if there’s no AC outlet available.


Now you have to decide what kind of interface you want on your hard-drive enclosure. Most drive enclosures feature USB or FireWire interfaces because they’re the most popular ones in use, and some feature a combination of both to make them more versatile. Most USB enclosures are USB 2.0, which is compatible with any USB port out there. But only USB 3.0 peripherals will deliver USB 3.0 performance, and that’s only when connected to a USB 3.0 port. More and more new computers feature USB 3.0 ports, so you might want to go with a USB 3.0 enclosure.

Installing a hard drive in an external enclosure is very easy; usually all you need is a screwdriver. In the worst case, you might have to move or remove a jumper that sets the drive to be a master or slave, but the odds are you won’t have to touch anything but your screwdriver. 

Once your external drive is working, you can connect it to a computer and pull any files you want from it. Then you can format the drive and start with a clean slate. If you are uncertain and feel as though you might need the assistance of professionals, contact the B&H computer service center.



Hi guys love the article was wondering if you could recommend a computer that i should build?

I have an old 4" sata Hitachi Model HDT721064SLA360 that was in an old PC that I don't care to resurrect and I'd like to grab the data off and use the drive as an external drive, if possible.  It looks like it has a standard SATA connector, but also has a small power connector also.  Do you have an adapter that would work for me?  Or would a standard USB to SATA adapter with an additional power source work for me?  Thanks!

Hello Sir,

Can I know whether I can access the files on the C drive of my hard disk, once i converted it into external unit

Once you convert the internal hard drive to an external hard drive, you can access the data from the drive.  Please note that it's likely your newly converted drive wouldn't be labeled as C:.

Hi Sir How Do I Get Back To My Face Book Home Page ?

Hello there. 

Please I have obtained the external casing for the old drive like it is described above. The issue is I had user accounts with password protection and so I cannot access the files.So all the files etc are locked up in folders. The current OS is an 8.1 while the former is a Windows 10

Hello thanks for the post, I have somewhat of a different question. So I'm planning on using my hard drive temporarily as an external hard disk on a different laptop. What happens when I insert it back to its parent computer? Would it still be able to load its pre-existing windows? Thank you. 

If you haven't reformatted the hard drive, you should still be able to use the same drive as your 1st computer's main/boot drive.  But I would still advise against doing this since something could go wrong.  You're essentially using your computer's main hard drive as your laptop's external drive.  Consider purchasing a very inexpensive 1TB external hard drive for the laptop.

Hi, so I know what kind of hard drive I have, I want to go to Belarc Advisor, but how do I get it from my Apps & Features?  thanks for any help to find this.      Rosa



If you've converted your internal hard drive to an external drive and you have that software in the drive, you would not be able to access the app from this drive.  You would need to reinstall this app to your computer's internal hard drive.


About a year ago I messed up my laptop by spilling wine all over the keyboard, and it had to be written off. The hard drive was still good, and it was converted into an external hard drive to get all my files back.

My problem: The old hard drive had 500Gb of memory. Yesterday I thought I could use it, and it only shows 19Gb. I have formatted it, and still the same. What happened to the rest of the Gb's?

I hope you can give me an answer to this?


Hi Karin,

What kind of computer are you using now (Mac or PC)?  What was the format you selected when reformatting your drive?

If I take my hard drive from my failing computer and make it an external drive for a new computer, will I still be able to run all the programs that have been installed on it?  The hard drive is a Samsung HD753LI SCSI.

Hi Jim!  You would not be able to run the programs off of the external hard drive.  The programs would have to be re-installed.

Nice partial article. Yes, you can use an enclosure if you wish but it's not really necessary. a usb adaptor can be had for $10-$15 and will run your hd as well as an enclosure. You can even construct your own enclosure easily out of anything from a cardboard box to a custom fabricated, Kevlar lined, titanium safe (don't know why you'd want to though

Steven, I have three or four old tower computers that have hard drives, but the ex decided to try to dismantle them and such in the divorce.  I would like to hook them up to my laptop and see if I can salvage the older family pix and such off them.  Is there an adapter to this, and if so, what is it called?  Thank you.

I need an external  adpater for an ols 3.5 inch asus hard drive

and necessary aux power supply and usb adapter pplug for hd

Hello! Can I ask for help? I turned my old laptop's hard drive into an external drive. It worked just fine before when I plug it on our desktop. When I got my new laptop, I reformatted my external hard drive and put new contents on there. After a month, I'm having trouble of accessing my files. My laptop is reading the hard drive and it actually shows the memory used. But when I try to open the hard drive, it only shows the first folder I have and it doesn't even has a content. I'm not actually very familiar with this technical stuff so I would be really greatful if you could tell me what I could do. Thank you very much

This does sound rather bizarre.  I don't know what the issue could be, possibly hard drive failure?  You may have to take your drive in to a recovery lab or you can try reaching out to our experts at [email protected] for insight.  

Thank you. I just learned that my hard drive was converted from NTFS to ReFS. When it became ReFS, it started not showing my files. Before, some of my files that are not inside any folder begun missing. Now, everything is missing :'(

Very informative article. My PC had a hitachi deskstar 500 GB hard drive model HDP725050DLA360.

It measures 5.5" X 4"

I want to use it as external hard drive placed in an enclosure.

Can you advise me which enclosure I need and where to get it from.

I observe that only 3.5" and 2.5" size enclosures are available at various websites.

You would need a 3.5" enclosure for your hard drive.  3.5" would refer to the diameter of the platter that's inside your drive, not the actual drive dimensions.  So just about any 3.5" enclosure would work with your Hitachi Deskstar hard drive.  

Great article. Thanks. Is there such a thing as a hard drive enclosure for a 4 inch hard drive? It's a Conners Peripherals from 1991. If not, is there a way to get the data off the drive? It was working when removed from the computer.

Thanks for your help.


We do not have an enclosure for your drive unfortunately. It may be possible to use an IDE to USB adapter for your drive.  But to be certain, can you provide us with your drive's model #?

I have the old hard drive from my windows 7 up laptop..I would like to know if I were to buy an enclosure would I be able to see and copy my old email folders, etc..I now have an  ASUS windows 10 laptop

Hi Judy - 

Sounds like a good plan Judy!

HEY Mark..thanks so much for your reply  

could I use a HP external drive and connect to a dell desk top to retrive all files and make a backup copy?

Hello admin,i have this hard drive that i just got an enclosure for,but unfortunately it installed but do not work with my new laptop but it is working perfectly well with my neighbour's laptop

Hey Temitope, 

For your inquiry, please contact our tech team directly by e-mailing [email protected].  Please be as thorough as possible and include information like what kind of computer you have, your friend has, specs, and operating system.

I have an old windows PC where I'd like to remove the hard drive and insert into an enclosure as above.  Not being terribly tecky with computers, I am wondering if I could plug this into my Mac and it would work, ie I could access all my photo's on it? I'm guessing it wouldnt work (that would be far too easy!!) but could ypu advise please? Thanks very much. 

This wouldn't be a problem at all.  Your Mac would be able to read your Windows (NTFS) drive without any special software.  You would just need to figure out if your hard drive is PATA or SATA.  Or if you're not too sure, you can get an enclosure that supports both types of drives like the one in the link below.

i hav all the above accessories mentioned above 

A 3.5 inch hdd

An old Seagate hard drive

but i cannot initialize that disk in my computer it is not showing only help me please

If your drive is not showing up, it's possible your drive is no good.  For further assistance, please contact our tech team by e-mailing [email protected].

my dell inspiron 15 5000 series died.. unfortunately it has data on it that I need.. I was advise to purchase:

I have also been told that I will need a driver specific to hard drive in order to extract the data from the hard drive.  does anyone have the link to that driver so I can download it?

SATA/PATA/IDE Drive to USB 2.0 Adapter Converter Cable for 2.5 / 3.5 Inch Hard Drive / 5 inch Optical Drive with External AC Power Adapter


You wouldn't need any driver.  If you are just trying to extract the data from this drive with your new computer, you would just need to install your old drive to an enclosure.  The enclosures are plug and play and your new computer should just read it as an external hard drive.

Problem in detecting external 2.5" sata casing in PC

I have purchased a new TECH-COM SSD-2501SATA a 2.5" casing runs with USB (No external power required). Then placed my WD Scorpio Blue 500GB Hard Disk in it then connected to laptop running windows 7. At the first when I connected drivers installed, but device not shown in Device Manager/ in Computer. A LED blowing in sata casing, we can recognize running of HD by touching it but not showing up. Previously HD is working in my old laptop now purchased new one so want to convert this drive to external drive it is formatted with NTFS with windows 8.1 pro installed in C drive have 4 partitions.

Please help me to solve this issue.

From your description, it sounds like your enclosure could be defective.  You should contact the retailer or the manufacturer for an exchange.


             I removed a SATA hard disk from my DELL LAPTOP and i want to use i as an external storage on other laptops,

             HOW CAN I DO THIS? give me the steps

There's nothing to it.  When you purchase an external enclosure for your 2.5" SATA hard drive, you would simply connect the drive to the board, slide the board into the enclosure, and close the enclosure with screws (if required).  This is true for just about every enclosure we carry.

Hi, I am having aproble with the connection. When i connect the ext. enclosure it doesnt let me initialize in dskmng. It show up in cmd as online but 0b as the size. I can clean it thru cmd but I cant turn it to a MBR. So its not reconizing on "my computer". ITs using the same driver as my primary hdd but it shows up as USB device in device manager. What am I missing? Can you help please, thanks.

Hi,I have  a lenovo laptop which has gone kaput, and have now gone back to HP.  Is there any way I can put the hard drive into an external enclosure, and reclaim any of my stuff.  I have a lot of important documents on the hard drive,along with Powerpoint shows, music and movies. I'm not very hopeful to be honest, but you guys know a lot more than myself, and maybe you can help .

Thanks a lot.



Absolutely!  You can use a simple 2.5" SATA Enclosure like the one below.  Once installed and connected to your HP computer, you can use your Lenovo drive as an external hard drive.

G'day sir,

               i took out a hard disk which just 80gb (from one of my oldest computer). Is there any way of using it in my new computer (Asus)

                Pls help me!!!!

Hi Ajay!  This shouldn't be a problem.  Though since it's an older computer, I'm not sure what kind of drive you have.  It's either SATA or IDE/PATA.  If you're not sure yourself, the best thing to do would be to contact our PC Sales Team directly at [email protected] and also include a picture of the back of the hard drive.

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