How to install an SSD

For most machines the fitting takes about ten minutes and one small screw. The drive goes in one way, and the machine finds it on the next boot. What takes an afternoon is moving your data across, and the decision behind that: copy the old drive over, or start clean.

What do you need before you start

Settle what your machine takes first. How many M.2 slots it has, what length each accepts, whether there is a 2.5-inch bay, and how much room sits above a slot are all on the manufacturer's support page. M.2 sizes and SSD form factors works through that table and what it leaves out. This guide starts once the right drive is on the desk.

Back up the old drive, not the new one. Pointing a tool at the wrong volume costs what you had, not what you paid.

Find the mounting hardware before you open anything. The screw that holds an M.2 drive down comes with the machine or the motherboard rather than with the drive.

Count the slots and bays again if you mean to copy the old drive over. Copying needs both drives readable at once, and a laptop with a single M.2 slot cannot hold both; one of the two has to sit in an external enclosure for the duration, in the order set out below.

Then power the machine down properly: shut the operating system down, switch the supply off, pull the cord, and hold the power button for a few seconds to drain the board. A desktop motherboard carries standby power the whole time the cord is in, so off is not the same as unplugged. On a laptop, disconnect the internal battery too if the service manual says the design allows it. Touch bare metal on the chassis before you touch the drive.

How does the drive actually go in

An M.2 drive goes in along its own plane rather than straight down. Line the notch up with the socket's key and slide the edge connector in at the slight upward angle the socket already holds the card at, pushing until the gold contacts disappear into it. It takes a firm push, not a hard one. Let go and the free end of the card stays up off the board.

Bring that free end down onto the threaded post and fasten it there. The card rests on top of the post, a little above the board rather than flat against it. Turn the screw until the card stops moving, then stop. The connector supplies the contact pressure, so the screw is only holding one end steady, and the threads it turns in strip easily. Some recent boards replace it with a toolless latch that twists over the end of the card, which does the same job.

A 2.5-inch drive is a bracket and two cables. It mounts in a bay, in a caddy, or on a 3.5-inch tray with an adapter. The narrow seven-pin lead is data and runs to a SATA port on the motherboard. The wider fifteen-pin lead is power and comes from the power supply. Both connectors are cut in an L so that each goes in one way only, and both should slide home without persuasion. A laptop drive usually pushes straight onto a connector in the bay instead, with no cables to route.

Should you clone or do a clean install

Cloning copies the old drive onto the new one: the operating system, the applications, the settings, the files, and whatever is already activated. You restart into the machine you had, on faster storage. It is the shorter path by hours, and it asks you to reinstall nothing.

It also copies what is wrong. A driver conflict, a half-removed application, and six years of things that start themselves at boot all move across intact.

A clean install is the opposite trade. The operating system goes on the new drive fresh, then you put back the applications you actually use and bring your files over from the old drive or the backup. It costs an afternoon, plus an evening of small forgotten things a week later. What it buys is a machine with nothing accumulated on it — the only dependable way to be rid of an accumulation nobody can name.

Neither one is the default. Clone if the machine has been behaving and you need it working tonight. Install clean if it has not been, or if this is the tidy-up you have been putting off.

Cloning also has an order. If the machine holds both drives at once, fit the new one and copy afterwards. If it holds only one, the new drive goes in the external enclosure and you copy onto it there, before the old drive comes out; the two then trade places, machine off as before. Pull the old drive first and there is nothing to copy from. A clean install needs no source and is free of this.

What happens on the first boot

A new drive arrives with nothing on it, and an empty drive does not appear in a file manager. Two separate steps make it usable. Initialising writes a fresh partition table to the drive you select, and to nothing else. Formatting is the step after, and puts a filesystem on the space so that files can be stored there. On a drive that has never been used there is nothing to lose in either. On a drive that has, both leave what was on it unreachable, which is why the drive you pick matters more than anything else on that screen.

Identify the target by capacity and by emptiness rather than by its letter or its label. This is where a clone bites: afterwards two drives carry the same volume name and the same contents, and size is all that separates them. If you cannot tell them apart, shut down and unplug one.

The other thing a clone leaves you with is two bootloaders. Both drives can now start the machine, and the firmware boots whichever its boot order names first, which may still be the old one — everything then looks correct and none of your work is doing anything. The clean way to check is to power down, unplug the old drive, and boot from the new one alone. Power down the same way to put it back as a spare, or wipe it for storage.

Last, confirm the capacity. A drive reporting far less room than it should is usually a partition question rather than a hardware one.

Why is the new drive not showing up

Start with seating, and power the machine down again by the sequence above. None of this is hot-pluggable. A card pushed in far enough to look right can still be a fraction short of contact, and the screw will hold it there. Take the screw out, push the card in again until the contacts are hidden, and fasten it once more. On a 2.5-inch drive, reseat both leads.

Then ask what the slot speaks. An M.2 socket carries NVMe, SATA, or both, and nothing on the outside of it says which. A drive in a slot that does not speak its protocol does not appear at all — not slowly, not partially. NVMe or SATA covers telling the two apart and finding out what a particular slot carries.

Then ask what else is using the lanes. On many boards a second M.2 slot borrows its lanes from SATA ports, so populating one disables the other, and the drive that disappears may be one that was working yesterday rather than the one you just fitted. The motherboard manual states which are paired.

Firmware is the last place to look. The setup screen lists storage before the operating system loads, so a drive present there and missing afterwards is a question about software rather than about fitting. Older boards sometimes want a firmware update before they will recognise a newer drive. Check too whether the board is set to a RAID or remap mode, which presents an NVMe drive behind a vendor storage controller rather than as a plain one.

How to choose an SSD covers the four questions that get you to the right drive in the first place, and every SSD we track is on one page.