External hard drive or flash drive not detected: how to fix it

Quick answer: why is my external drive not showing up?

The most common causes, from easiest to hardest, are:

• A faulty or charge-only cable, or a damaged USB port.
• Not enough power, especially for portable hard drives on a laptop.
• The drive is detected but has no drive letter, or is offline in Disk Management.
• A driver or Windows glitch.
• A damaged file system, shown as RAW or unallocated.
• A failing drive or a damaged connector inside the enclosure.

Work through the sections in order. The first few steps cost nothing and cannot hurt your data. Before you start, one rule: do not format, repartition or run repair tools on a drive that holds files you need. Those actions are for later, after your files are safe.

Step 1: check the cable, port and power

1. Unplug the drive, wait ten seconds and plug it in again, firmly but gently.
2. Change the USB port. Use a port directly on the laptop, not a hub or extension. Try one at the back of a desktop computer rather than the front.
3. Change the cable. Cables fail often, and some cables only charge and do not carry data. Use the cable that came with the drive if you still have it.
4. Look and listen. Does the drive light come on? Can you hear or feel it spinning? A portable hard drive that gets no light at all may not be getting enough power.
5. Try a different computer. This is the most useful test of all. If the drive works elsewhere, the problem is your laptop, not the drive.

Power. Portable hard drives draw their power from the USB port. A weak port, a long cable, or a hub shared with other devices can give too little. Some drives come with a Y-shaped cable that uses two ports for extra power. Large desktop-style external drives have their own power adapter. Check that it is plugged in, switched on, and is the correct adapter for that drive, as a wrong adapter can cause damage.

Flash drives rarely have power problems, but their connectors wear out. If the drive only works when you hold it at an angle, it is physically damaged. Stop pushing it and copy off what you can.

Step 2: look in File Explorer and Disk Management

The drive may be connected but hidden from the places you normally look.

1. Open File Explorer and click This PC. Look under Devices and drives.
2. If it is not there, right-click the Start button and click Disk Management.
3. Look through the list and the grey panels at the bottom. Find a disk that matches the size of your drive.

What you see tells you what to do:

• The drive shows as Online with a file system (NTFS, exFAT or FAT32) but no drive letter. This is the easiest fix; see Step 3.
• The drive shows as Offline. Right-click the disk number on the left and click Online.
• It shows as RAW, or as Unallocated. The file system or partition information is damaged. Your files may still be there. Do not format. See the section on when your data is at risk.
• It shows as Not Initialized. Do not initialise it if it held your files, because that can make recovery harder. Get advice first.
• It does not appear at all. Go to Step 4, then try another computer.

Step 3: assign a drive letter (the fix that works most often)

1. In Disk Management, right-click the partition of your drive (the main bar, not the disk label).
2. Click Change Drive Letter and Paths.
3. Click Add if there is no letter, or Change if there is one.
4. Pick a letter that is not in use, such as E, F or G, and click OK.

The drive should appear in File Explorer within seconds. A drive can also fail to appear when it was given the same letter as a mapped network folder, so choosing a letter later in the alphabet helps.

If the menu option is greyed out, Windows cannot read the file system, which usually points to a damaged or unsupported partition.

A note on drives formatted for other systems. A drive formatted on a Mac (APFS or Mac OS Extended) or for Linux will not be readable in Windows. It is not broken. You will need to use it on that kind of computer, or ask a technician to copy files off it.

Step 4: update or reinstall the USB driver

If Windows makes the connection sound but nothing opens, or the drive appears with a yellow warning mark, reinstall its driver. It is safe and Windows re-creates it.

1. Right-click Start and open Device Manager.
2. Expand Disk drives and Universal Serial Bus controllers. Look for your drive or an item marked Unknown device or with a yellow triangle.
3. Right-click it and choose Uninstall device. Do not tick the option to delete driver software unless you are asked to.
4. Unplug the drive, restart the laptop, then plug the drive in again.

Next, check USB power saving, which can switch ports off. Open Control Panel, Power Options, Change plan settings, Change advanced power settings, then USB settings, USB selective suspend setting. Set it to Disabled and click OK.

Finally, install pending Windows updates, then try again. Update the laptop's chipset and USB drivers only from the laptop maker's official support page.

When Windows says you need to format the disk

This message is the most dangerous moment for your files:

You need to format the disk in drive E: before you can use it.

Do not click Format disk. Click Cancel. The message means Windows cannot read the file system. It does not mean the drive is empty. Formatting writes a new structure to the drive, which makes recovery harder or impossible, especially after a full format.

Instead:

1. Close the box. Safely remove the drive and stop using it.
2. Try it on another computer. If it opens there, copy your files to a safe place immediately.
3. If it still shows RAW, unallocated or asks for formatting, take the drive to a technician who can read it without writing to it.

Avoid running chkdsk /f on a drive with important files unless you have already copied them or have no other choice. It rewrites file system structures and can make things worse on a damaged disk.

When your data is at risk: stop and get recovery help

Switch the drive off and stop trying fixes if you notice any of these:

• Clicking, ticking, grinding or repeated beeping from a hard drive.
• The drive spins up, spins down, then repeats.
• The drive was dropped, knocked while running, or got wet.
• The drive is detected but extremely slow, or freezes your laptop when you open it.
• The drive appears and disappears, or shows a wrong size such as a few megabytes.
• You can smell burning or the drive is very hot.

These are signs of physical damage. Powering it on again and again can scrape the surface of a hard drive or wear a damaged flash chip further. Recovery for physical faults needs special equipment, which is why a professional assessment comes before any repair attempt. Do not put a hard drive in a freezer and do not open it; both ideas are myths that destroy data.

Once you have recovered your files, replace the drive. A drive that has failed once should not hold your only copy of anything.

How to stop this happening again

• Use Safely Remove Hardware (the small USB icon near the clock) before unplugging. Pulling out a drive mid-write is a leading cause of damaged file systems.
• Keep at least two copies of anything important, for example the laptop and an external drive, plus one cloud copy. A single external drive is a backup only while it still works.
• Do not carry a portable hard drive while it is running, and give it a protective case.
• Do not plug a drive into unfamiliar public computers, which spread viruses.
• Replace old drives. Portable hard drives wear out; plan to replace one that is several years old and heavily used.

Frequently asked questions

Written by the ICT AccessPoint team

We repair laptops and build websites and business systems. Have a question this guide did not answer? Message us.

This guide is general advice. Every device and business is different, so if you are unsure, ask a technician before you act.