You switch on your computer or plug in an external drive and, instead of the usual soft whirr as the platters spin up, you hear a low hum or buzz. Sometimes it lasts a few seconds and stops, sometimes it repeats, and the drive never appears in Windows, macOS or the BIOS. This is one of the more serious hard drive symptoms, and what you do in the next few minutes can decide whether your files are recoverable. This guide explains what the sound usually means and what to do (and avoid) to keep your data safe.
What a humming or buzzing hard drive usually means
A traditional hard drive has spinning platters and read/write heads that float a tiny distance above them. When power is applied, the spindle motor tries to bring the platters up to speed. A hum or buzz with no spin-up normally means the motor is receiving power but the platters cannot turn. The common causes are:
- Stuck heads (stiction). The heads should rest on a parking ramp or a landing zone when the drive is off. After a drop, a power cut or a sudden shutdown they can end up stuck to the platter surface, and the motor is not strong enough to break them free. This is especially common in 2.5-inch laptop and portable drives, where it is often heard as a buzz or a series of beeps.
- A seized spindle motor. The motor bearing can fail or seize, typically after impact or long use, so the platters cannot rotate even though the electronics are working.
- Insufficient power. On USB drives, a weak port, a long or damaged cable, or a passive USB hub can leave the drive without enough current to spin up. This is the one cause you can safely rule out yourself.
Stuck heads and a seized motor are internal mechanical faults. They cannot be fixed with software, and the drive’s circuit board is usually not the problem.
Why you should stop powering it on
It is natural to keep trying in the hope that the drive “catches”. Unfortunately, every attempt carries risk:
- If the heads are stuck to the platter and the motor does manage to jerk the platters free, the heads can be torn or bent, and damaged heads then scratch the surface where your data is stored.
- Repeatedly stalling the motor puts strain on the motor driver chip on the circuit board, which can then fail as well.
- If the platters begin to spin with damaged heads, a hum can quickly turn into clicking or scraping, which usually means physical damage is now happening.
A drive with stuck heads but undamaged platters is often a good candidate for recovery. The aim is to keep it in that state.
Things not to try
There is a lot of advice online for “fixing” a drive that will not spin. Most of it gambles with your data:
- Tapping, shaking or twisting the drive while it is powered. This can free the heads, but it is just as likely to damage them or the platter surface.
- The freezer trick. Cold does not fix stuck heads or a seized motor, and condensation forms on the platters and electronics when the drive warms up again.
- Opening the drive. The inside of a hard drive must be kept free of dust. Removing the lid outside a clean room lets particles settle on the platters, and a single particle can cause a head crash once the drive spins.
- Swapping the circuit board. A board swap will not free stuck heads, and modern drives store unique calibration data on the board, so a replacement from another drive rarely works anyway.
- Running repair or recovery software. If the platters do not spin, the computer cannot see the drive at all, so there is nothing for the software to work on.
What you can safely check
Before deciding the drive has a mechanical fault, it is worth ruling out power problems, with no more than one or two attempts:
- For a USB external drive, connect it directly to a USB port on the computer (on a desktop, a rear port) rather than through a hub, keyboard or monitor.
- Try a different, short cable. Many portable drives use a USB 3.0 Micro-B or USB-C cable, and a worn cable can drop the voltage.
- For desktop external drives with a separate mains adapter, make sure you are using the original adapter. An adapter with the wrong voltage can damage the drive’s electronics.
- Listen carefully. A drive that spins up normally (a rising whirr) but is not recognised has a different problem from one that only hums.
If the drive still only hums or buzzes, unplug it and leave it disconnected. Do not keep it plugged in “just in case”.
Internal drives in laptops and desktops
If the humming drive is inside a computer, shut the computer down and leave it off. If you are comfortable doing so, removing the drive for safe keeping is fine, but do not test it in another machine or a USB adapter repeatedly. Make a note of the drive’s make, model and serial number from its label, and of anything that happened before the fault (a knock, a power cut, a sudden shutdown). That history helps an engineer diagnose the fault quickly.
How the data is recovered
When heads are stuck or a motor has seized, recovery work has to be carried out inside a clean room. Depending on what is found, engineers may free and inspect the heads, replace the head assembly with matching parts from a compatible donor drive, or move the platters to a working mechanism. The drive is then read with specialist hardware that copies the data to a healthy drive, so the original is not stressed further. Our hard drive data recovery service explains more about this work, and you can see our wider range of options on the services page.
The earlier this happens, the better. A drive that has only ever hummed has usually suffered far less damage than one that has been forced to spin dozens of times.
Need help with a humming hard drive?
If your hard drive is humming, buzzing or beeping and will not spin, switch it off and get in touch before trying anything else. Data Doctor offers a free initial consultation, and our clean room is at Unit 1 The Willows, 80 Willow Walk, London SE1 5SY. Call us on 020 7394 2529 to talk through the symptoms with an engineer.