New SSD or hard drive not showing up in Windows? Initialise it in Disk Management (MBR or GPT)
You fitted a new SSD, Windows started fine, and the drive is nowhere in File Explorer. Usually nothing is wrong: new drives come completely blank, without even a partition table, and Windows only shows drives that have a volume on them.
Step by step
- Right-click Start (or press Win + X) and choose Disk Management.
- If an Initialize Disk box appears, tick the new disk, choose GPT (GUID Partition Table) and click OK. No box? Right-click the grey label on the left that says Disk 1 (or similar) Unknown, Not Initialized and choose Initialize Disk.
- Right-click the black Unallocated bar and choose New Simple Volume. Keep the full size, pick a drive letter, format as NTFS with a name such as "Data", and leave Perform a quick format ticked.
- Click Finish. The drive appears in File Explorer under This PC.
Check the size before you click anything: the new disk is the one whose size matches the drive you bought and that has no partitions yet. Your Windows drive (usually Disk 0) has several partitions, including one marked Boot or C:. Leave that one alone.
MBR or GPT?
| Pick | When |
|---|---|
| GPT | Almost always: any drive in a PC from the last decade, any drive over 2 TB, and any drive you might install Windows 11 onto. |
| MBR | Only for very old computers that can't start from GPT, or a small stick or drive that a car stereo, older TV or camera has to read. |
MBR can't use more than 2 TB of a drive, which is why a big drive set up as MBR shows a chunk of space you can't use. The partition table explainer covers what the difference actually is.
What the drive says in Disk Management
| You see | What it means | Do this |
|---|---|---|
| Unknown, Not Initialized | Brand new drive, no partition table yet | Initialise as GPT, then New Simple Volume |
| Online, all Unallocated | Initialised but no volume | New Simple Volume |
| Healthy partition, no drive letter | The volume exists but Windows didn't give it a letter | Right-click it, Change Drive Letter and Paths, Add |
| RAW | Windows can't read the file system | New drive: format it. Drive with files: see "You need to format the disk" first |
| Offline | Windows has set it aside, sometimes after a signature clash with a cloned drive | Right-click the disk label and choose Online |
| Not listed at all | Windows can't see the hardware | See the next section |
Not in Disk Management at all?
- Check the BIOS or UEFI setup (press Del, F2 or F10 at power-on). If the drive isn't listed there either, it's a hardware or connection problem, not Windows.
- M.2 drives: make sure it's fully seated and screwed down. Some motherboards share lanes, so a second M.2 slot is switched off when certain SATA ports are in use, or only takes NVMe or only SATA M.2 drives. The motherboard manual has a table.
- SATA drives: they need both a data cable to the motherboard and a power cable from the power supply. Try another SATA port and cable.
- Installing Windows and the drive is missing: some Intel systems use RST or VMD mode, and Windows Setup needs the storage driver loaded (Load driver) from the maker's support page, or VMD switched off in the BIOS.
- In a USB enclosure: try another cable and port, and see USB drive not showing up.
Why the size looks smaller
A "1 TB" drive shows as about 931 GB in Windows. Nothing is missing: drive makers count 1 TB as 1,000,000,000,000 bytes, while Windows counts in binary units (1 GB = 1,073,741,824 bytes) but still labels them GB. The unit converter shows the sum.
Related
SSD slower than advertised · Clone your old drive to the new SSD · SSD health percentage explained · "You need to format the disk before you can use it" · USB stick or external drive not showing up · Which format for a USB stick · Wipe a drive before giving it away
Questions
Why is my new SSD not showing up in File Explorer?
New drives come blank. Open Disk Management, initialise the disk (choose GPT), then right-click the unallocated space and create a New Simple Volume. It then appears with a drive letter.
Should I initialise a new SSD as MBR or GPT?
GPT, almost always. Use MBR only for very old computers or small drives a car stereo, TV or camera must read. MBR can't use more than 2 TB.
Does initialising a disk erase it?
Yes, it writes a new partition table, so only initialise a new, empty drive. If a drive that had files suddenly says Not Initialized, stop and recover the files first.
My SSD shows in the BIOS but not in Windows. Why?
It probably just needs initialising and a volume in Disk Management. If it's missing from Disk Management, update the storage or chipset driver.
Why does my 1 TB drive show as 931 GB?
Drive makers use 1 TB = 10^12 bytes; Windows counts in binary units but calls them GB, so 10^12 bytes shows as about 931 GB. No space is missing.
Published · updated .