How to Convert an Old Laptop Hard Drive into an External USB Drive: DIY Guide

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29 December 2025

If you have an old laptop lying around, its hard drive doesn’t have to go to waste. With a few inexpensive tools, you can recycle that unused drive and turn it into a fully functional external USB drive for backups, file storage, or data transfer.

This DIY approach not only saves money but also helps extend the life of your hardware. Whether you’re upgrading a laptop or repurposing an old HDD, the process is simpler than most people expect.

In this guide, you’ll learn how to convert a 2.5 inch laptop hard drive into an external USB drive safely, step by step, with practical tips along the way.

How to Convert an Old Laptop Hard Drive into an External USB Drive: DIY Guide

Here's a complete DIY (Do It Yourself) guide that lets you use any 2.5 inch laptop hard drive HDD or SSD as a portable external hard drive.

Tools Required

To repurpose an old laptop hard drive safely and reliably, you’ll need the following:

• A 2.5-inch internal laptop HDD or SSD
  Salvaged from an older laptop. Most laptop drives use the SATA interface and typically support SATA II (3 Gbps) or SATA III (6 Gbps) speeds. Both are fully compatible with modern USB-to-SATA solutions. Here, hard drive brands do not matter. Your hard drive may be from WD Western Digital, Seagate, Toshiba or Hitachi.

• A 2.5-inch external hard drive enclosure (recommended for beginners)
  An enclosure protects the drive, requires no technical setup, and usually offers tool-free installation, making it the safest option if you have limited PC hardware experience.

• A SATA-to-USB 3.0 adapter cable (for experienced users)
  Suitable if you’re comfortable handling bare drives. This option offers flexibility but requires careful handling of the exposed drive.

Important: Whether you choose an enclosure or a SATA-to-USB adapter cable, ensure it uses a reliable USB-to-SATA bridge controller such as the ASM1153 or ASM225CM. Cheap enclosures or cables with older or unbranded controllers may fail to deliver expected USB 3.0 transfer speeds and can cause connection or stability issues.

Steps to Connect The Internal Laptop Hard Drive to PC Through USB

After getting the required tools, let's now learn to connect the laptop hard drive or SSD to PC/Mac over USB.

1. Make sure you don't have anything important on the laptop hard drive that you're going to use as external.
2. Connect the laptop hard drive either to the USB to SATA cable or the 2.5 inch enclosure.
3. Now connect the hard drive to PC or a different laptop to a USB 2.0 or 3.0 port on your laptop or PC.
4. After connecting the hard drive or the SSD to PC over USB, you may see multiple partitions from the previous OS installation.
5. We have to delete these partitions from the hard drive and use the entire drive's storage as a single partition only.
6. To create, delete and manage disk partitions, we'll use disk management console on Windows 10 and Windows 11.
7. To open disk management console, press the Windows key + R to open the run prompt, then type 'diskmgmt.msc' and hit the 'Enter' key.
8. In the 'Disk Management' console you'll see 'Disk 0' which is PC/laptop's main internal drive that contains the operating system and your files. You do not have to touch 'Drive 0'.

Warning: Never touch 'Disk 0' in the disk management console. 'Disk 0' is the main disk containing the operating system, your personal files, apps, installed programs and system partition. Make sure to have a backup of your laptop/PC's main disk on a different drive or external storage.

9. If your PC/laptop has only one internal hard disk or SSD, then the 2.5 inch hard drive you connect to your laptop via USB will appear as 'Disk 1' in disk management console.

10. Just next to 'Disk 1' you will see separate partitions. Right click on every partition and select 'Delete Volume' to delete that partition.
11. Once you delete all the volumes/partitions on your 2.5 inch external USB HDD, you will see unallocated space on that drive.
12. See the image below, I am using a 500 GB internal laptop drive as external drive over USB 3.0. I have also deleted all the partitions on this 'Disk 1' and I am now left with 465.76 GB on this drive.

13. Right click on the unallocated space in 'Disk 1' and click 'New Simple Volume.' A 'New Simple Volume Wizard' will open, click 'Next' to proceed.

14. In this step, you will be asked to specify the drive size. But because we are using entire drive's storage space in a single partition, then we do not have to specify the size, because by default the volume creating wizard picks up the entire storage size in MBs (Mega Bytes). Click 'Next' to proceed.

15. In this step, you will be asked to assign a letter to your drive. The system automatically assigns the best letter for your hard drive, so you don't have to choose manually. Click 'Next' to proceed.

16. Now we have to format the HDD/SSD. In the 'File system' option, make sure to select 'NTFS' or 'exFAT'. If you use this 2.5 inch hard drive primarily with your Windows PC, Linux and Android TVs then select 'NTFS' only. If you're using an SSD instead of internal HDD then you can choose exFAT partition scheme to make it work even with smartphones: Android and iPhones. SSDs have low power consumption so, they're safe to work with smartphones with an exFAT partition scheme. Also read: How to Transfer Files Between Android and Windows PCs — Step-by-Step Guide

17. In the 'Volume label:' type a name such as 'External Storage' as this will help you identify this hard drive/SSD in 'My PC' when connected.
18. Make sure 'Perform a quick format' option is checked, then click 'Next' to proceed and then finally click 'Finish.'
19. Now open 'My PC' and you will see your laptop's 2.5 HDD or SSD with a label name 'External Storage.'
20. We've successfully converted an internal 2.5 laptop hard drive or SSD to an external storage device connected via USB. But this is not it as we have to check the disk's health before moving or copying data to it.

How to Check Internal Hard Drive For Bad Sectors Before Using It As External Storage

Now that you have learned to use 2.5 inch internal hard drives as external storage, we must ensure that the concerned HDDs are free from any bad sectors and read write errors. If the hard drive reports any bad sectors then we won't use it to store important data.

Hard drives with bad sectors can fail any time and over time such a drive will develop more bad sectors. Bad sectors are a clear sign of mechanical wear and an early warning that at some time the drive would definitely fail.

Warning: A hard drive or SSD with bad sectors must not be used to store important data. You also never use such a HDD as your primary backup drive. Eventually, it will fail at some point. Storing important data on such a drive will result in data loss and file corruption beyond recovery. You can use this drive just for storing unimportant data such as movies.

Now, let's move on to check the 2.5 inch hard drive for errors and bad sectors.

How to Use CHKDSK to Check Hard Drive's Health and Identify Bad Sectors

In this section, we're using chkdsk command on Windows 10/11 to check the hard drive's health. Our purpose here is to find out whether the drive we're about to use is reliable to be used as an external storage device.

1. Connect the 2.5 inch internal HDD to your Windows PC by using the SATA to USB cable or enclosure.
2. Make sure the drive is visible in 'My PC' with a label 'External Storage' that we created earlier.
3. Note the drive label for this externally connected internal hard drive. 'F:' is the drive letter in my case.
4. Open command prompt (CMD) with administrator privileges. To do this, type 'CMD' in Windows search box, once you see 'Command Prompt,' right click on it and select 'Run as administrator.'
5. In the command prompt type: chkdsk X: /r. Replace X: with your drive's letter. After correctly typing the command, hit enter and let chkdsk perform a thorough scan of the hard drive.

6. For a 500 GB hard drive, chkdsk will take about more than an hour to finish the drive scan before returning the results.
7. If chkdsk reports no bad sectors or errors then you can use this drive as an external storage.

I used CHKDSK on my 12-year-old 2.5-inch internal hard disk from Hitachi HGST and it reported 8 KB in bad sectors. This means a very small portion of the disk’s physical surface has become unreadable and has been permanently marked as unusable by the file system.

In practical terms, 8 KB is an extremely small amount of space, but its presence confirms that the drive has started to suffer from physical wear, which is expected at this age. While the operating system will avoid using these damaged sectors, their appearance indicates that the disk is no longer in perfect health and may continue to degrade over time.

The drive may still function for light or non-critical use, but it should not be trusted with important data, and maintaining regular backups—or planning a replacement—is strongly recommended.

How to Find Hard Drive Errors and Early Signs Of Failing Using SMART (S.M.A.R.T) Data

Every internal hard drive or SSD or even external hard drives come with S.M.A.R.T technology. S.M.A.R.T. (Self-Monitoring, Analysis, and Reporting Technology) is a hard drive health monitoring system.

By analysing SMART data we can detect the early warning signs of a hard disk failure. A hard disk won't fail suddenly in many cases, therefore we always have time to transfer data to a new drive.

So, let's see how can we analyze the SMART data for your 2.5 inch internal hard disk to detect read/write errors, bad sectors and early signs of failing.

1. Download and install CrystalDiskInfo. If you don't wish to install it, you can also download the portable .zip package.
2. CrystalDiskInfo is only available for Windows 10/11. If you're using a Mac then you can use Apple's Disk Utility.
3. Make sure to connect your 2.5 inch internal HDD/SSD to your PC/laptop using the SATA to USB cable or enclosure.
4. After downloading CrystalDiskInfo, open it by double clicking DiskInfo64.exe.
5. In CrystalDiskInfo, click the drive with only one partition. You can also check the name of your 2.5 inch HDD in CrystalDiskInfo that'll help you identify it.
6. If CrystalDiskInfo shows no warnings and displays the status as 'Good' then you can use this hard drive/SSD as an external storage device.
7. But if you see any warning or status as 'Caution' then it is an early warning sign of hard drive or SSD failure.

The same Hitachi hard drive now shows a Current Pending Sector Count of 100 in CrystalDiskInfo. This means there are many sectors on the disk that the drive is struggling to read and has not yet been able to repair or permanently mark as bad.

Unlike confirmed bad sectors reported by CHKDSK, pending sectors indicate ongoing instability and a much higher risk of sudden data loss. At this level, the drive is clearly in poor health and may degrade quickly with continued use.

While it might still operate for short periods, it should no longer be considered reliable, and replacing the drive is strongly recommended. Therefore, I'm not using this drive for regular backups. I'll use this drive to store only unimportant data.

How to Use 3.5 Inch HDD As External?

So far, I have talked about an SSD and a 2.5 inch internal hard drive in this post. But does this post apply to 3.5 inch desktop hard drives? Yes! this post is equally applicable to desktop hard drives.

However, you need the right tools to use your desktop hard drive as external storage. A 3.5 inch desktop hard disk requires 12V supply which a USB port can't do. Therefore, you need a 3.5 inch hard drive bay with a dedicated 12V power supply.

Once you gather the required tools, you can start converting your old desktop hard drives to external storage.

Conclusion

Repurposing old laptop or desktop hard drives is an easy, cost-effective way to create reliable external storage while reducing electronic waste. By following this step-by-step guide, you can safely convert 2.5-inch or 3.5-inch drives into USB-ready devices for backups, file transfers, or extra storage. Remember to check for bad sectors and monitor drive health to protect your data. Don’t let unused drives gather dust—take action today! Gather your tools, follow the instructions, and turn your old drives into practical, portable storage solutions that make your digital life more organized and efficient.

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