You connect your external hard drive or start your computer, expecting the drive to appear in File Explorer (Windows) or Finder (macOS)—but it’s missing. A hard drive not showing up is a common and highly disruptive issue that can block access to important files. It can affect both internal and external drives across Windows and Mac systems. Causes range from simple configuration problems to serious hardware failures. This guide outlines a systematic troubleshooting approach, beginning with basic checks and prioritizing data safety at every step.
Step 1: Is the Drive Recognized at the Lowest Level? (BIOS/UEFI Check - "Not Detected")
Before troubleshooting within the operating system, we need to see if the computer’s fundamental input/output system (BIOS or UEFI) even recognizes that the hardware exists. If the drive is not detected here, it certainly won’t show up in Windows or macOS.
How to Check BIOS/UEFI
- Restart your computer.
- Enter Setup: As it boots, press the key indicated on screen to enter Setup, BIOS, or UEFI. Common keys include Del, F2, F1, F10, F12, or Esc. You may need to look up the specific key for your motherboard manufacturer.
- Look for Drive Information: Navigate through the menus (often under sections like “Boot,” “Storage,” “SATA Configuration,” or “System Information”). Look for a list of connected SATA or NVMe drives.
- Check Boot Order: Also, check the boot sequence/order. Is your primary hard drive listed and set as the first boot device (unless you intend to boot from USB/DVD)?
What If Hard Drive Is Not Detected in BIOS/UEFI?
If the drive is completely absent from the BIOS/UEFI list:
- Check Physical Connections (Internal Drives – Use Caution): If you are comfortable working inside your computer case and understand static discharge precautions, power off completely, unplug the computer, and check that both the data (SATA or NVMe) and power cables are securely connected to the drive and the motherboard/power supply. Reseating them carefully can sometimes help. If unsure, skip this and seek professional help.
- Check Power (External Drives): Ensure the external drive’s power adapter (if it has one) is plugged in and functional. Try a different wall outlet. Ensure the USB cable is firmly connected at both ends. Try a different USB port on your computer.
- Listen/Feel for Spin-Up: Does the drive make any sound or vibrate when power is applied? If it remains completely silent and still, it might not be receiving power or could have a critical failure like a seized motor or dead PCB. Refer to our guide if your Hard Drive Is Not Spinning.
- Potential Hardware Failure: If connections and power seem okay, but the drive is still not detected in BIOS/UEFI, it strongly suggests a serious hardware issue with the drive itself (PCB failure, internal mechanical/electronic failure) or potentially the motherboard port. Further DIY troubleshooting is highly risky. Data recovery requires professional intervention at this stage.
Step 2: Detected in BIOS, But Not Showing Up in the OS? (Checking Disk Management/Disk Utility)
If the drive is listed in the BIOS/UEFI but still doesn’t appear in File Explorer or Finder, the issue likely lies within the operating system’s configuration or the drive’s logical structure. We need to use the OS disk management tools.
Using Disk Management (Windows)
- Right-click the Start button (or press Win + X).
- Select “Disk Management.”
- Look for your drive in the list (usually displayed as “Disk 0”, “Disk 1”, etc., in the lower pane).
Using Disk Utility (macOS)
Go to Applications > Utilities > Disk Utility.
Ensure “View” (in the top menu bar or top-left corner) is set to “Show All Devices.”
Look for your drive listed in the left-hand sidebar (it might show the manufacturer name or connection type like USB).
What to Look For in Disk Management / Disk Utility
Even if the drive doesn’t appear with a letter or volume name, it might show up here in one of these states:
- Healthy, but No Drive Letter (Windows): The partitions are listed with file systems (NTFS, FAT32), but no drive letter (like D:, E:) is assigned.
- Not Initialized / Unknown / Unallocated: The drive is listed, but the space shows as “Not Initialized” or completely “Unallocated.” This often happens with brand new drives or drives whose partition table is corrupted.
- RAW File System: A partition is listed, but the file system type is shown as “RAW.” This indicates file system corruption.
- Listed but Not Mounted (macOS): The drive or its volumes appear in Disk Utility but are greyed out, indicating they are not mounted (made accessible).
- Foreign Disk (Windows Server/RAID): Indicates a disk that was part of a different system’s dynamic disk or RAID setup.
Step 3: Addressing Common OS-Level Issues (Proceed with Caution!)
If your drive appears in Disk Management or Disk Utility but not File Explorer/Finder, here are common reasons and potential actions. WARNING: Some actions, like initializing or formatting, WILL ERASE DATA. Proceed only if you are certain the drive contains no needed data or after successful data recovery.
Assigning a Drive Letter (Windows)
- Problem: Drive is healthy and formatted but lacks a drive letter.
- Action (Relatively Safe): In Disk Management, right-click the partition (the healthy volume), select “Change Drive Letter and Paths…”, click “Add”, choose a letter, and click OK.
- Risk: Minimal risk if the partition is healthy.
Mounting a Volume (macOS)
Problem: Drive/volume appears in Disk Utility but is greyed out (unmounted).
Action (Relatively Safe): Select the greyed-out volume (not the parent drive) in Disk Utility and click the “Mount” button in the toolbar. If it mounts successfully, it should appear in Finder.
Risk: Minimal risk if the underlying file system is healthy. Failure to mount often indicates corruption. For more Mac-specific troubleshooting, especially with external drives, see our dedicated post: External Hard Drive Not Showing Up.
Initializing a Disk (Windows/macOS - DATA LOSS RISK!)
Problem: Drive shows as “Not Initialized” or “Unknown.” Often occurs with new, blank drives.
Action (ERASES DATA): In Disk Management, right-click the disk name (e.g., Disk 1) and choose “Initialize Disk.” Select a partition style (GPT is modern standard, MBR for older compatibility). On Mac, Disk Utility might prompt to initialize or use “Erase” on the parent drive. THIS WIPES ALL EXISTING DATA.
Risk: Guaranteed data loss if the drive wasn’t blank. Only do this for brand new drives or if you’ve already recovered needed data professionally. If a previously working drive suddenly shows as uninitialized, it likely indicates severe partition table corruption requiring data recovery before initialization.
RAW File System / Corruption (DATA LOSS RISK!)
Problem: Drive/partition shows as RAW or fails to mount due to corruption. Windows/macOS might prompt you to format it.
Action (DO NOT FORMAT): Formatting a RAW drive will erase the data. Standard repair tools (chkdsk, Disk Utility First Aid) are risky and can worsen data loss (see previous posts). The safest path is professional data recovery.
Risk: Formatting causes complete data loss. Running risky repair tools can too. Learn more about safe approaches in our Corrupted Hard Drive Recovery Guide.
Unsupported File System
Problem: Drive is formatted with a file system your current OS doesn’t natively support (e.g., Linux Ext4 on Windows/Mac, macOS APFS on Windows).
Action: Use a computer with the compatible OS, or install third-party software/drivers that enable reading the file system (use reputable sources). Formatting is not required if you just need read access on an incompatible system.
Internal SSD Specifics
Modern NVMe SSDs sometimes require specific drivers or BIOS settings (like NVMe mode enabled). If an internal SSD isn’t showing up, check motherboard manufacturer support for driver/BIOS updates.
Step 4: Recognizing Signs of Physical Failure
If the simple logical fixes above don’t work, or if you observe other symptoms, physical failure becomes more likely:
- Drive Not Detected in BIOS/UEFI: As discussed in Step 1, this usually points to hardware issues.
- Clicking, Grinding, Beeping: Any unusual noises indicate mechanical failure requiring immediate power-off and professional help.
- Drive Disappears Intermittently: The drive might show up sometimes but vanish during use, suggesting failing components or connection issues.
- Very Slow Performance: Extreme sluggishness before it stopped showing up can indicate developing bad sectors or failing heads.
- S.M.A.R.T. Warnings: If you previously received drive health warnings from monitoring tools.
If physical failure is suspected, stop all troubleshooting attempts immediately to prevent further damage.
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Step 5: When Professional Data Recovery is the Necessary Path
DIY troubleshooting has its limits, especially when hardware failure or severe corruption is involved. Professional data recovery is strongly recommended if:
- The drive is not detected in the BIOS/UEFI.
- The drive makes any physical noises (clicking, grinding, beeping).
- The drive shows as RAW or uninitialized/unallocated, and contains critical data.
- Simple fixes (drive letter, mount) fail, and the data is valuable.
- You suspect physical damage or failure.
- You are uncomfortable performing technical troubleshooting steps.
Professionals use specialized hardware, software, and cleanroom environments (for physical issues) to maximize data recovery chances while minimizing risk. Trying further DIY steps in these scenarios often makes professional recovery harder or impossible. Learn more about our service by visiting the Hard Drive Data Recovery page.
Preventing Future "Not Showing Up" Issues
While failures can happen, good practices help:
- Safely Eject Drives: Always use the proper procedure before unplugging external drives.
- Use Quality Cables/Power Supplies: Avoid stressing connectors or providing unstable power.
- Protect from Shocks/Impacts: Handle drives carefully.
- Monitor Drive Health (Basic): Occasionally check S.M.A.R.T. status.
- Maintain Backups: The only true protection against data loss from any failure.
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Conclusion: Systematic Checks and Prioritizing Data
A hard drive not showing up can be caused by anything from a simple missing drive letter to catastrophic hardware failure. By systematically checking BIOS/UEFI detection first, then examining the drive’s status in OS disk management tools, you can narrow down the potential cause. Remember the cardinal rule: prioritize your data. Avoid any potentially destructive actions like initializing, formatting, or running repair utilities (chkdsk, First Aid) on drives containing important data, especially if you suspect corruption or hardware issues. When in doubt, or if the drive is physically failing or not detected at a basic level, professional data recovery offers the safest path forward. For more context, explore our guide on Common Hard Drive Problems.
Frequently Asked Questions
Why is my external hard drive not showing up on my Mac but works on Windows?
This is almost always due to file system incompatibility. The drive is likely formatted as NTFS (Windows standard), which macOS can read but not natively write to without third-party software. Reformatting as exFAT makes it compatible with both, but erases data. Alternatively, use macOS NTFS driver software.
My hard drive shows up in Disk Management as "Unallocated." Can I get data back?
Possibly, but do not create a new volume or format it. “Unallocated” means the partition information is gone. Data might still physically exist but requires professional recovery tools to scan the raw space and rebuild the lost partition structure or carve files directly.
Can updating drivers fix a hard drive not showing up?
Sometimes, especially for specific storage controllers or external devices, an outdated or corrupted driver can cause detection issues within the OS (even if seen in BIOS). Updating motherboard chipset drivers or specific device drivers can help in some cases, but it’s less common for simple non-detection than partition/file system issues or hardware failure.
My new hard drive isn't showing up. What did I do wrong?
Usually nothing! New drives often ship uninitialized and unformatted. You typically need to go into Disk Management (Windows) or Disk Utility (macOS), initialize the disk (choose GPT partition style), and then create and format a new volume/partition before it will appear in File Explorer/Finder.
Is it safe to assign a drive letter if Disk Management shows the partition as healthy?
Generally, yes. Assigning a drive letter in Windows is usually a safe, non-destructive operation if Disk Management correctly identifies the partition and its file system (e.g., NTFS, exFAT).
