First of all, it is essential to check if the cable is functioning correctly. Also, there could potentially be an issue with the USB port, so it is best to try another port first. If the drive is detected, but not accessible, attempt to repair the file allocation table using the system’s disk utility.
FAQ about hard drives not being detected
Below are the most frequent questions we are asked regarding unrecognised hard drives.
My hard drive can't be accessed but is recognised by BIOS
If your hard drive is spinning without a problem but is not recognised by your computer's BIOs this an be a sign of logical failure. This type of failure can be the result of defective media or data corruption from another source. In this case, first check the jumpers, which will vary according to the configuration of the hard drive. You should also check that the connectors and power supply are properly connected. In severe cases, there may be a problem with the circuit board. In the majority of logical failures, you should be able to recover the data via a data recovery software.
My hard drive is not recognised and appears dead
A burnt circuit board (PCB) is one of the most common problems seen in hard drives. A power surge, overheating or an inadequate power supply can result in a hard drive frying its spindle driver chip leaving the data inaccessible.
In some older models, you may be able to swap the PCB from another model. But most modern hard drives have logic boards that have been adapted to the head disk it was manufactured with. In those cases, a data recovery specialist will need to rebuild the parameters or transfer them from the fried board to the donor PCB to make it fully compatible with the damaged hard drive.
My hard drive is not being detected by Windows
One of the most common questions we hear is, "Microsoft Windows on my PC is not recognising my hard drive. What should I do?". Firstly, you should restart your computer, check the connections and plug your external hard drive into another PC. If the problem persists, there could be two reasons:
The disk is still not recognised by Windows – If you have checked the connections and plugged your hard drive into another PC, but it is still not recognised, the hard drive could be defective.
The hard drive does not appear in Windows Explorer 10, 7 or 8 but is detected by the computer – there could be a letter assignment problem in Disk Management – the hard drive doesn't have a letter by its name, so Windows File Explorer won't be able to detect the disk partition. To assign a drive letter to it, follow these steps:
- Right-click on the workstation icon on your desktop
- Click on 'Manage' and then on 'Disk Management' in the Computer Management window
- Select 'change drive letter and paths'
- In this window, click on 'Add' to assign a drive letter to hard drive partition or click 'change' to change the drive letter.
My hard drive is not being detected on my Mac
In this case, you should first check whether your external hard drive is recognised by another system. If you have access to a Windows or Linux PC, plug your external hard drive in; if it is recognised, perform a repair from the terminal, you can do this with the commands' diskutil list' and 'diskutil info disk'. Improper removal of the device can cause damage, so ensure you safely remove the drive before unplugging the external hard drive.
If the external hard drive is not recognised when you plug it back into the Mac, first ensure your USB cable enables the USB port's auto-power function. If the hard drive is still not recognised, verify that the 'Finder' settings allow you to view newly connected devices. If your hard drive is NTFS formatted, non-native to the Mac, the Read Utility may need to be reset (Paragon NTFS us available in most versions of the Mac OS). If the external hard drive continues not to be readable and is not visible on the BIOS of other systems (Windows or Linux), then a hardware failure should be considered.
Why is my external hard drive not recognised by my MAC?
It could be as simple as the USB cable being worn out or that the utility of the Mac is misconfigured and is not displaying any connected devices. If the hard drive is not partitioned in HFS+ format, the Mac OS X format, or ExFat format, verify that your utility is correctly installed.
If you have checked all of the above, there could be a hardware problem. In this case, you will need to contact a data recovery specialist.
How to access an unrecognised hard drive?
It may seem simple but change the USB port and check that your USB cable is functioning properly. If the hard drive is appearing in the utility but is not accessible, you will need to repair it using the terminal commands. If the hard drive continues not to be recognised, you may have to use a data recovery software to locate the files.
Is updating drivers a solution?
When your hard drive is detected by your computer but is not displayed in Windows Explorer, you can try to update the driver. To do this, you should follow these instructions:
- Open the "Device Manager".
- Right-click on the start button then click on "device manager". In this list, a coloured indicator may appear to indicate any errors.
- In the "Disk drive" section, you will find the reference of your disk. Right-click on it then click on "Update Driver". The update will automatically be taken over by Windows Update.
Should I format my hard drive?
You should only format your drive if you have no data (or data you do not need) residing on it. You will need to choose the right format that suits your computer. Opt for NTFS or FAT32 if you are on Windows, and HFS +, ExFat or Mac OS Extended if on Mac.
Remember that formatting a hard drive will erase all the stored data, so only choose this method if your hard drive is empty.
![SSDs, USB sticks and memory cards SSDs, USB sticks and memory cards](https://assets.ontrack.com/cms/images/ontrack/in-page-assets/img_600x600_usbgroup.png?sfvrsn=47354d9d_16)
SSD drives, USB sticks, and memory cards: what you need to know
Unlike mechanical hard drives, SSDs, USB sticks and memory cards are based on flash memory and have no moving parts.
A flash device may not be recognised by the system due to dirty or defective connectors. Carefully cleaning them with the help of a cotton wool bud, lightly dipped in alcohol, then letting it dry thoroughly, may solve the problem.
Alternatively, it is possible that access becomes difficult, or even impossible. This is often linked to a failure in the storage unit clusters. If the SSD, USB or memory card is new, this could be a defect covered by warranty. In other cases, it could be due to excessive usage or wear and tear.
It is important to know that flash memory units have several writing/suppression cycles limited for each cluster, going from 1,000 to over 100,000 depending on the quality of the product. When this limit is reached, access is more difficult and it becomes a pressing matter to consider saving the data elsewhere. If the drive becomes totally inaccessible, professional data recovery is necessary.