Why it happens
A new SSD is uninitialized — it has no partition table. Windows File Explorer only shows formatted, lettered drives.
Fix via Disk Management
- Press Win+X → Disk Management.
- The new SSD appears at the bottom as "Unknown / Not Initialized".
- Right-click the disk icon (left side) → Initialize Disk → Select GPT → OK.
- Right-click the unallocated space → New Simple Volume → follow the wizard.
- Assign a drive letter and format as NTFS.
If it does not appear in Disk Management
- Check SATA/power cables are fully seated.
- For M.2 NVMe: ensure it is fully inserted and the retention screw is in.
- Check Device Manager for any unknown devices with yellow marks.
- Some BIOS versions need NVMe support enabled — check under Storage configuration.