The drive is missing
The drive is not showing up.
What to check, in order, before you format.
A drive that disappears is more frightening than one that makes noise, because it feels like the bad thing has already happened. Usually it has not: in most cases the drive is fine and the problem sits between it and the computer. But there is a way to make things genuinely worse in one second, and it is the first thing many people try.
First: do not format, do not initialise
If Windows offers to format the drive, or Disk Management asks you to initialise it, say no.
Those two words sound like repair and they are not. Formatting wipes the index of what is on the drive; initialising rewrites the partition table, which is the map saying where your material begins. A drive that is not recognised because of a cable, a port or a system flag stays full and recoverable until something writes to it. Those two operations write to it.
Everything else on this page can be tried without touching a single byte on the drive.
Can you hear it spin?
The obvious question that solves more cases than all the clever ones put together. Put a hand on the drive and listen.
| What you hear | What it means |
|---|---|
| Nothing. No vibration, no light | It is not getting power. Change the cable and the port, and if the drive has its own power supply try a different one. USB cables fail inside the connector, where you cannot see it. A 3.5-inch drive running off a hub with no power of its own often will not spin up at all. |
| It spins steadily, but the computer shows nothing | The drive is alive: the problem is downstream, and that is what the rest of this page is about. |
| It starts, stops, starts again | Almost always still power, not a dying drive. Try it on a port on the computer itself rather than a hub, with no extension cable. |
| A repeating click | This is the one case where it is worth stopping. Do not keep replugging it: every attempt is another risk. What actually warns you → |
The computer can see it. You cannot.
This is the most common case of all, and you check it in one place. Press Windows+X and open Disk Management; on a Mac open Disk Utility and turn on Show All Devices in the View menu.
| How it appears | What is going on |
|---|---|
| It is there, correct size, but no drive letter | The drive and the data are all present: what is missing is the name Windows shows it under. Assign a letter and it comes back with its contents untouched. The most common case, and the least serious. |
| It is there, marked Offline | Windows can see it and has decided not to mount it. This is not a fault, and it is the case the next section is about — the one that catches everybody out. |
| It is there, but entirely Unallocated | The partition map cannot be read. The data is often still there, but this is also where Windows offers to initialise. Do not. If the material matters, this is the moment to stop and talk to a data recovery lab. |
| It is there, but the file system says RAW | The drive responds, the format cannot be interpreted. Same rule as above: do not format. A RAW drive that has been formatted is an empty drive. |
If the drive came from a Mac and you are looking at it on Windows — or the other way round — it can look perfectly healthy and unreadable at the same time. That is a format the other system cannot read without a driver. It is not broken, and formatting it to make it readable is exactly the wrong fix.
The case nobody expects: the drive is offline
It gets its own section because it is common, it takes seconds to fix, and its cause is nowhere near where anyone would look.
When a program ejects a drive and cannot do it cleanly, the fallback nearly everyone uses — ours included, until recently — is to mark it offline. It is safe for the data and looks harmless. The catch is that the flag does not clear itself: plug the drive back in and it returns offline, with no letter, invisible in File Explorer.
And there is a detail that makes it genuinely baffling: Windows does not attach that flag to the drive, it attaches it to the slot — bus type, enclosure model and port address. Take that drive out, put a different one into the same dock, and the new drive arrives offline too, though you never ejected it. Hence the feeling that the dock has died, or that two drives failed at once.
Two ways to fix it. By hand: in Disk Management, right-click the disk name on the left, Online. Or let the program do it — see below.
If it is not in Disk Management either
Here the list gets short, and almost none of it is about your files.
Where a program helps, and where it does not
Start with what no program can do, so there is no doubt left.
No software brings back a drive that will not spin, and anyone promising otherwise is selling something else. If the material really matters, the only serious route is a data recovery lab, and every attempt made beforehand makes their job harder.
The useful things are three, and they are smaller than they sound.
First: knowing what was on it. That is the question that arrives right after the fright, and without a catalogue it has no answer. NanoTracker keeps the folder list of every drive it has seen at least once: with that drive unplugged, dead or unrecoverable, you can still read what it held and work out whether a copy exists elsewhere. It is also the only way to answer the question that decides everything — is it worth paying to recover?
Second: USB drives left offline. The ones from the section above. NanoTracker notices them itself and brings them back online, including drives that something else marked offline: an external drive sitting offline is never a choice the user made. Internal drives are left alone, because there that state can be deliberate.
Third: the drive letter. If it is missing, or taken by something else, you change it from the drive card without going through Disk Management — which matters most when an editing project is looking for files on one specific letter.
And if the drive does show up but you do not trust it, you can read its health from there — coming soon for Windows and macOS. Which numbers actually matter →
Common questions
Windows is asking me to format the drive. Will I lose everything?
Yes, in the sense that matters: a quick format does not erase your files one by one, but it wipes the index that says where they are, and from that moment the system treats all that space as free to reuse. Anything written afterwards can land on top of your material. A drive asking to be formatted is not saying I am empty: it is saying I cannot read my own index, which is an entirely different thing.
The drive shows in Disk Management but not in File Explorer. Why?
Because File Explorer only shows volumes mounted with a letter. If the drive is listed at its correct size, the data is there: what is missing is the name it gets shown under, or the disk is marked Offline. Those are the two least serious cases on this page, and neither one touches your content.
I ejected it and now it is gone. Did I break something?
Almost certainly not: this is the drive-left-offline case. It happens when an eject cannot complete cleanly and falls back to that state. The flag attaches to the slot — bus, enclosure model, port — rather than to the drive, which is why it can also hit the next drive you put in the same dock. It clears in two clicks, and your data was never involved.
The drive makes a noise but the computer will not see it. Should I keep trying?
No. A repeating click is the one signal on this page that asks you to stop. Every replug is another read attempt on a mechanism that is already struggling. If there is something on it you cannot lose, this is the moment to stop and call a lab, not to try a fifth time.
It shows on one computer but not the other. Which one is at fault?
The one that cannot see it — and that is good news, because it means the drive is fine. Check the port, then the cable, then the format: a drive prepared on a Mac can be unreadable on Windows without anything being broken. That is not a reason to format it.
How can I find out what was on a drive I can no longer open?
Only if something catalogued it beforehand. That is why programs like this one exist: NanoTracker records the folders of every drive you connect, and that list stays readable when the drive itself is gone. If the drive was never catalogued by anything, there is no way to reconstruct what it held — which is exactly the situation worth not living through twice.
The day a drive will not open, there is only one question: what was on it?
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