Short answer: uLaunchELF reads USB drives only when they are formatted FAT32 with an MBR (Master Boot Record) partition table. If your drive is NTFS, exFAT, or GPT-partitioned, mass:/ shows empty or freezes. Reformat the drive to FAT32/MBR on a PC, copy the installer files again, and it will appear.

Check the format first

• On Windows, open Disk Management and check the drive’s partition style (MBR vs GPT) and filesystem (FAT32 vs NTFS/exFAT).
• On macOS/Linux, check with Disk Utility / lsblk + blkid. If it says GPT or NTFS or exFAT, that is your answer.
• Drives over 32GB cannot be formatted to FAT32 with Windows’ built-in tool alone — use a third-party formatter (Rufus or GUIFormat are the FAQ’s named examples) to force FAT32 on a larger drive, or use a smaller drive for the installer (an 8GB or smaller stick is ideal for this job).

Reformat correctly

• Back up anything on the drive first — reformatting erases it.
• Convert the partition table to MBR (in Disk Management: delete volumes, then convert; or use diskpart clean + convert mbr — be certain you picked the right disk).
• Format as FAT32, default allocation size is fine for installer files.
• Copy the FreeMCBoot or Fortuna installer files to the drive root again, eject safely, and reinsert it into the PS2.
• In uLaunchELF FileBrowser, open mass:/ — the files should now list.

If it still fails

• Try the other USB port on the PS2. Front-port power and contact vary with age.
• Try a different, smaller, plain USB 2.0 stick. Some large or USB 3.0-only sticks with fancy controllers confuse the PS2’s USB 1.1 hardware.
• If mass:/ freezes uLaunchELF entirely (not just empty), remove the drive, reboot, and reformat — a frozen browser is the same filesystem problem, not a broken console.
• Do not confuse this with OPL storage: OPL USB loading also wants FAT32, but MX4SIO and HDD loading have their own formats (see OPL storage comparison).

Next steps

• uLaunchELF basics
• Install FreeMCBoot with FreeDVDBoot
• Install kit buying guide

Verified against: PS2 USB 1.1 / uLaunchELF mass:/ FAT32 + MBR requirement per ConsoleMods and uLaunchELF documentation; >32GB Windows FAT32 limit is a Windows tool limitation, checked 2026-10-24.