Your drive is connected but invisible — start with the basics
An external hard drive that does not appear on your computer usually has one of four causes: the cable is loose or damaged, the drive needs power and is not getting it, your operating system has not recognized the hardware yet, or the drive itself has failed. Most of the time it is the cable. Before you assume the drive is broken, work through each of these in order — they take minutes to check and most people find the problem in the first two steps.
The drive may appear in your system settings or device manager even when it does not show up on your desktop or in File Explorer. That tells you the hardware is recognized but the drive is not mounted — a different problem with a different fix. This guide walks you through what to check first, how to mount a drive your system sees but does not display, and when the drive itself is the problem.
Key Takeaways
- Disconnect the drive completely, wait ten seconds, and reconnect it to the same port — this fixes most cases where the connection is loose or the system needs to re-detect the hardware.
- If your drive requires a separate power adapter, plug it in directly to an outlet rather than a USB hub, because hubs often cannot supply enough power.
- Check Device Manager (Windows) or System Report (Mac) to see whether your system recognizes the drive at all — if it does, the drive is not broken and you can mount it manually.
- Try a different USB port and a different cable before concluding the drive has failed, because both fail more often than the drive itself does.
- If the drive appears in your system settings but not in File Explorer, it is usually unmounted and needs to be mounted or initialized before use.
Check the cable and power connection first
Disconnect the external drive from your computer completely. If the drive has a separate power adapter (a brick or cord plugged into the wall), unplug that too. Wait ten seconds, then plug the power adapter back in if it has one. Plug the USB cable into the same port you were using before and wait thirty seconds for your system to detect it.
If the drive still does not appear, try a different USB port on your computer. Do not use a USB hub or a port on a monitor, keyboard, or docking station — plug directly into a port on the computer itself. Hubs and secondary ports often cannot supply enough power, especially for larger external drives.
If you have access to a different cable, swap it out and try again. USB cables fail frequently and a damaged cable is one of the most common reasons a drive does not show up. If you have a second computer nearby, plug the drive into that computer using the same cable. If it appears on the second computer, your original computer's port or system is the problem. If it does not appear on any computer, the drive itself is likely the issue.
Verify your system recognizes the drive in Device Manager or System Report
On Windows: Right-click the Start button and select Device Manager. Look for a category called Disk Drives or Universal Serial Bus Controllers. Expand it. If you see your external drive listed there — even if it has a warning icon or says "Unknown Device" — your computer recognizes the hardware. The drive is not broken; it is just not mounted or assigned a drive letter.
On Mac: Click the Apple menu, select About This Mac, then click System Report. Click USB in the left sidebar. If your external drive appears in the list on the right, your Mac recognizes it. If it shows a status other than "OK" or if it does not appear at all, try the next section.
If your drive does not appear in Device Manager or System Report after you have tried multiple ports and cables, the drive hardware is likely not communicating with your computer. This usually means the drive has failed internally, but it can also mean a port on your computer is damaged. Try the drive on a second computer if you can. If it does not appear on any computer, the drive needs replacement.
Mount or initialize the drive if your system recognizes it
On Windows: If the drive appears in Device Manager but not on your desktop, it may not have a drive letter assigned. Right-click the drive in Device Manager and select Properties. Note the disk number (Disk 1, Disk 2, etc.). Open Disk Management by right-clicking the Start button and selecting Disk Management. Find the disk that matches the number you noted. If it shows as "Unallocated" or "Unknown", right-click it and select Initialize Disk. Choose MBR or GPT (GPT is standard for newer systems) and click OK. Then right-click the unallocated space and select New straightforward Volume. Follow the wizard to create a partition and assign a drive letter.
If the drive already shows a partition in Disk Management but still does not appear in File Explorer, right-click the partition and select Properties. Check whether it is marked as a healthy volume. If it is, right-click it again and select "Mark Partition as Active" if that option appears. If the partition shows as "RAW" instead of NTFS or FAT32, the file system is corrupted and the drive will need to be reformatted — this erases all data on it.
On Mac: If the drive appears in System Report but not on your desktop, open Disk Utility (search for it in Spotlight). Look for your external drive in the list on the left. If it appears but is grayed out or shows as unmounted, click it and click the Mount button at the top. If no Mount button appears, the drive may need to be initialized. Click the drive, click Erase at the top, choose a format (Mac OS Extended for older Macs, APFS for newer ones), give it a name, and click Erase. This erases all data on the drive.
What to do if the drive appears but shows as corrupted or unreadable
If your system recognizes the drive but cannot read it — it shows as RAW in Windows Disk Management, or Disk Utility says it cannot read the format — the file system is damaged. On Windows, you can try to repair it using the command line. Open Command Prompt as Administrator, type chkdsk X: /F (replace X with your drive letter), and press Enter. This scans the drive and attempts to fix errors. It may take several minutes.
On Mac, open Disk Utility, click the drive, and click First Aid at the top. This runs a repair scan similar to chkdsk. If either tool reports that it cannot repair the drive, the file system is too damaged to recover without specialized software or professional data recovery — and recovery is expensive. If you have important files on the drive, do not attempt further repairs yourself.
If the drive is not important or you have backups elsewhere, you can reformat it to make it usable again. This erases all data. In Windows Disk Management, right-click the drive and select Format. In Mac Disk Utility, click the drive and click Erase. Both will wipe the drive and prepare it for use.
Test the drive on a different computer if you have one available
If you have access to a second computer — a friend's laptop, a work computer, or a library computer — plug your external drive into it using your cable. If the drive appears on the second computer, your original computer's USB ports or system software is the problem, not the drive. If it does not appear on any computer, the drive hardware has failed.
Testing on a second computer also tells you whether the problem is specific to your operating system. A drive that works on a Mac but not on Windows (or vice versa) may have a file system your computer does not recognize. Windows reads NTFS and FAT32. Macs read APFS and Mac OS Extended. If your drive is formatted in a system your computer does not support, you can reformat it, but this erases all data on it.
When the drive itself has failed
If the drive does not appear on any computer, does not show up in Device Manager or System Report even after trying multiple ports and cables, or makes clicking or beeping sounds when powered on, the drive hardware has likely failed. External drives contain moving parts and can fail suddenly, especially if they have been dropped, exposed to heat, or used for many years.
If you have important data on the drive, do not open it yourself or attempt to repair it — this usually makes recovery impossible. Professional data recovery services can sometimes retrieve files from a failed drive, but the cost is high (often $300 to $1,500 or more). If the drive is not important or you have backups, you can replace it. If you need the data and cannot afford recovery, contact a local computer repair shop to ask whether they offer data recovery or can recommend a service.
Frequently Asked Questions
Why does my drive work on one computer but not another?
The most common reason is a file system mismatch. Windows computers cannot read Mac-formatted drives without additional software, and Macs cannot read some Windows formats. The drive itself is fine — you just need to reformat it for the computer you want to use it on. Reformatting erases all data, so back up anything important first.
My drive shows up in Device Manager but not in File Explorer. What do I do?
The drive is recognized but not mounted or assigned a drive letter. Open Disk Management, find your drive in the list, and check whether it has a partition. If it shows unallocated space, right-click it and create a new straightforward volume. If it already has a partition, right-click the partition and make sure it is assigned a drive letter.
The drive makes a clicking sound when I plug it in. Is it broken?
Clicking or beeping usually means the drive's internal components are failing. Stop using it when ready — continued use can make recovery impossible. If you have important files on it, contact a data recovery service. Do not open the drive yourself.
Can I fix a drive that shows as RAW in Disk Management?
You can try running chkdsk to repair the file system, but if that fails, the file system is too damaged to recover without professional help. If the data is not important, you can reformat the drive to make it usable again, but this erases everything on it.
Do I need to eject the drive before unplugging it?
Yes. On Windows, right-click the drive in File Explorer and select Eject. On Mac, click the eject icon next to the drive name in Finder. This tells your system to stop using the drive before you unplug it. Unplugging without ejecting can corrupt files or damage the file system.