Attaching a second hard drive is an effective method of extending space on your computer. But, the extra drive not showing up on Windows is not such a rare problem.
Since your computer has an already installed primary hard drive, the BIOS configuration can cause detection problems for the second drive. Or disk driver issues are also something to blame, not to mention connection issues and drive letter assignment issues.
Table of Contents
How to Fix Second Hard Drive Not Showing Up Issue
Before moving on to solutions, you should ensure the connection between your second hard drive and computer is good. Then, you can try the given solutions:
Enable from BIOS
BIOS, your computer’s firmware, can act as a switch to enable or disable attached I/O devices. And BIOS have settings to auto-detect such drives when booting.
The first hard drive connected to your computer would be configured as the Primary hard drive, and any subsequent would be the Secondary one. So, make sure you have the right settings configured.
- Restart your computer and before it starts, press the BIOS key (Function keys like F2 or F8 generally) constantly.
- Once the BIOS loads, Go to the CMOS setup category.
- Choose Auto for all options.
If the list doesn’t consist of your second disk, ensure proper connection of the disk with the computer.
Check Connection

Interruption between the physical connection of Hard drive and computer can also cause the discussed issue. Faulty ports, cables, or even slots may be the actual reason behind the interruption.
To ensure that isn’t the issue, try to reconnect the cables and if necessary, reseat the device properly. You can also use different sets of cables.
Using a different slot of your computer would help you narrow down the issue even further. Then if the problem persists, connect the hard drive to another PC. If it works on another computer, BIOS may have been misconfigured.
Reset BIOS
The misconfiguration of BIOS can be fixed by resetting the BIOS settings to default factory settings. The exact steps for BIOS differ according to the motherboard. However, general steps would include:
- Enter BIOS by constantly pressing BIOS key while starting up your computer.
- Go to Reset BIOS or Restore Default within the BIOS menu.
- Press the instructed key and follow the onscreen steps to Reset BIOS.
Hardware Troubleshooter
You can apply a quick fix by running the Windows hardware and devices troubleshooter. It would automatically scan and resolve fixable issues for any connected hardware device, including the second hard drive.
- Open Run with Windows + R.
- Type
msdt.exe -id DeviceDiagnostic
and hit Enter to open troubleshooter. - Click on the Next button and follow the onscreen instructions to complete.
Fix Driver Issues
Then, the first software problem that you should try to resolve would be related to the disk driver. Windows operating system tries to communicate with your hard drive using driver software but if it’s outdated or corrupted, drive detection issues will arise.
- Press Windows + R to open Run.
- Type
devmgmt.msc
and press Enter key to open Device Manager. - Double-click and expand the Disk drives.
- Right-click on the disk driver and choose Update driver.
- Select Search automatically for drivers and let Windows do its job.
But, if no update is available, or the update didn’t fix your issue, you can try to reinstall the driver.
- Open Device Manager.
- Expand the Disk drives category and right-click on the driver.
- Choose Uninstall device.
- Click on the Uninstall button to confirm.
- Now, click on the Action menu at the top and select Scan for hardware changes.
The second disk’s driver should reappear.
Rescan Disks
Scanning a new piece of hardware attached to the system is an automatic process of Windows. But sometimes, it may not do, so you can manually scan and detect your hard drive from the Disk Management utility.
- Open Run with Windows + R.
- Type
diskmgmt.msc
and hit Enter to open Disk Management. - Click on the Action Menu and Choose Rescan Disks.
Initialize Disk
If the disk is visible in Disk Management but not in Windows Explorer, chances are the disk itself isn’t initialized. It is possible if the hard drive is new or recently formatted. To fix it, you can initialize the disk.
- Open Run and go to Disk Management.
- Right-click on the Disk and pick Online.
- And right-click on it again and choose Initialize.
- Select GPT partition style and hit Ok.
Allocate the Drive Space
After initializing the disk, the next step would be to create a volume within it so, that the space lists on Windows Explorer. It would also be helpful for already initialized Hard disk having unallocated space marked:
- Then, right-click on the unallocated space of your second hard drive and choose New Simple Volume…
- Hit the Next button to continue.
- Enter any desired size, or let it remain as default for the entire space within the drive and hit Next.
- Pick a Drive letter from the drop-down menu and click the Next button.
- You can select the desired File system, allocation unit size from respective drop-downs and also enter a label for your volume. Or, click on the Next button with the defaults.
- Hit the Finish button to complete.
Now instead of showing unallocated space, the space should be shown New Volume along with the drive letter, its size and the file system (NTFS by default).
Note: These steps will remove all the data within your hard drive, so it is not recommended if your drive has crucial data.
Assign Drive Letter
If the issue wasn’t of the driver or unallocated space, Windows might be experiencing a drive letter assignment problem. The operating system needs to assign some drive letter to your hard drive partition/volume in order to show it up in Windows explorer.
The process should be automatic, but in rare cases, Windows might not assign any drive letter. To resolve the issue,
- Open Disk Management.
- Right-click on your drive and choose Change Drive Letter and Paths…
- Click on the Add button if the drive hasn’t been assigned with any drive letter. Choose the Change button if it has got one.
- Select the desired drive letter (the lowest-ordered alphabetical letter like D, E, F, etc., would be better) from the drop-down.
- Hit the OK button and then OK again.
Format Data and Recover Drive
Accessing the hard drive sometimes becomes impossible if it is corrupted with bad sectors and partitions. So, you will have to format it first to make it usable. But, after formatting, the data within it’s gone? Not at all; even after formatting the drive or deleting everything from the drive, you will be able to recover data unless you have overwritten it.
To format the drive, open diskmgmt.msc
and follow the steps below:
- Right-click on your hard drive and choose Format…
- Let the settings remain default or configure it as desired and hit OK.
- Click on OK again to confirm the prompt.
Now, to recover the formatted data, open-source software called Test disk can be used. Download it from their website and continue with the steps below:
- Right-click the zip file and select Extract All…
- Hit the Browse… button and choose a location, and hit Extract.
- Now go to the extracted folder, and open
testdisk_win.exe
. - Click on the Run button and then Yes to confirm.
- Enter to create a log file.
- Use the up/down arrow keys to select the hard drive and press Enter.
- Pick the Partition table type or continue with the detected one.
- Hit Enter with the Analyse option and then Quick Search.
- After it scans, press P to look for files within the shown partition.
- Select the file to recover with the up/down arrow and hit the C key to copy.
- Choose a directory and hit Y to paste. (avoid moving to the same hard drive)
- Copy done message means recovery is successful.
- Continue the same with all the required files.
Other third-party paid software would provide GUI experience and are also able to recover directory structures.
Replace/Repair
If the hard drive doesn’t show up in any instance, it might be physically broken. But repairing on your own won’t be possible if you haven’t got hardware-related expertise. So, visiting a repair center or contacting a technician is recommended.