Ubuntu Installer Shows Only the USB Drive: Find the Missing SSD

The manual-partitioning screen is not proof that every physical disk was detected. If it shows one device around 123 GB with a VFAT partition while the computer should contain a 512 GB SSD, the 123 GB device is probably the USB installer—not an empty internal disk waiting to be partitioned.

Recognize the real beginner symptom

Imagine the installer displays only:

• One device around 114.6 GB or 123 GB.
• One VFAT partition.
• No device near the expected 256 GB, 512 GB, or 1 TB internal drive.

In the live session, a command produces this anonymized example:

NAME    SIZE   TYPE FSTYPE MODEL   MOUNTPOINTS
sda     114.6G disk        SanDisk
└─sda1  114.6G part vfat            /cdrom

The SanDisk model, USB-sized capacity, VFAT filesystem, and /cdrom mount point form a strong set of clues that /dev/sda is the live installation USB. The name /dev/sda does not decide this by itself.

Run the read-only check again

Return to the live desktop. Open Terminal. The prompt belongs to the terminal and is not part of the command.

lsblk -o NAME,SIZE,TYPE,FSTYPE,MODEL,MOUNTPOINTS

Press Enter. Compare every disk row with:

• The model and size of the USB in your hand.
• The internal-drive details recorded in Lesson 1.1.
• The /cdrom mount point used by the live media.
• The expected shape of an NVMe name such as nvme0n1 or a SATA name such as sda—without assuming either name is guaranteed.

If the internal model and capacity do not appear, the installer cannot safely use that disk yet.

Follow this diagnostic sequence

1. Close or back out of the installer without confirming a disk operation.
2. Return to the live desktop.
3. Run the single lsblk command above.
4. Identify the USB using model, capacity, filesystem, and /cdrom context.
5. Restart into UEFI setup and check whether the firmware lists the internal SSD or hard drive.
6. Reconfirm whether Windows must be preserved.
7. Inspect only the documented storage setting for terms such as RST, RAID, VMD, controller mode, or AHCI.
8. Continue to the branch below rather than changing several settings at once.

Decision tree: where the disk disappears

UEFI or BIOS does not detect the internal drive

Ubuntu cannot make firmware detect missing hardware. The cause may be a failed or disconnected disk, a disabled slot, a firmware configuration, or another hardware problem.

Do not continue with Ubuntu partitioning. Record the model and firmware screen, restore any setting you changed, and use the computer manufacturer’s official diagnostics or service documentation.

Firmware detects the drive, but Ubuntu does not

The hardware connection exists. On many Intel systems, enabled RST, VMD, or RAID controller configuration can hide or group storage in a way the installer cannot access. This is a common possibility, not a diagnosis proven by the symptom alone.

Continue to Intel RST, VMD, RAID, and AHCI Explained for Ubuntu and compare the exact firmware labels with the manufacturer’s documentation.

Windows must be preserved

Do not switch RST, RAID, VMD, or AHCI blindly. Windows may have been installed for the current controller mode and can fail to boot after a direct change. Back up files, retrieve the BitLocker recovery key, and follow Canonical’s complete Windows-to-AHCI preparation.

Also read BitLocker and Ubuntu Dual Boot before returning to the installer.

Windows will be erased

A full backup is still required because firmware and disk decisions can be wrong. Record the original storage setting, confirm the firmware sees the internal drive, and change only the documented controller option. Boot the live USB again and rerun lsblk. Do not start the installer until the internal model and capacity appear.

Did disabling RST cause the missing disk?

Usually the troubleshooting direction is the opposite: enabled RST, VMD, or RAID is a common reason Ubuntu cannot access a disk, and changing to an appropriate AHCI-style configuration may expose it. But a screenshot taken after several changes cannot prove the original cause.

Use evidence:

• Was the internal drive visible in firmware before and after?
• What was the original controller setting?
• Did lsblk change after exactly one controlled modification?
• Does Windows still boot when it must be preserved?

Record original values so a reversible change can be undone.

Common mistakes and recovery

Creating a new partition table on the USB. Stop immediately. Recreate the installation USB from the ISO if it was changed, then diagnose the internal controller before returning.

Assuming sda means hard drive. USB and SATA device names depend on detection order. Match model, capacity, partitions, and mount points.

Changing storage mode and Secure Boot together. You lose the ability to tell which change mattered and can trigger Windows recovery. Restore the original values and restart with one documented branch.

Continuing because “Erase disk” must find the SSD later. The installer cannot safely target an absent device. Close it.

What to learn next

Continue to Intel RST, VMD, RAID, and AHCI Explained for Ubuntu. If Windows must remain, read the BitLocker dual-boot preparation before any controller change.