Three weeks from submission, a West End student’s iMac restarted into the flashing question-mark folder — the Mac’s way of saying it can no longer find itself. Behind it sat a Fusion Drive, and inside that sat four years of research.
The machine had restarted for a macOS update and never come back. Two well-meant attempts at Disk Utility’s First Aid had already been made — both failing, mercifully, without “fixing” anything — and internet advice was about to suggest reinstalling macOS when the student rang instead. The iMac came to Bath Street that afternoon with the update half-applied and the thesis directory unreachable.
Fusion Drives are a partnership — a small SSD fronting a large hard disk, presented to macOS as one volume. The update had been interrupted while shuffling data between the partners, and the logical glue tying them together was corrupted: each half was individually healthy, but the combined volume no longer parsed. First Aid can’t mend that; a reinstall would have written straight over the very structures that made reunification possible.
SSD and hard disk were each imaged in full, then the Fusion relationship was reconstructed virtually from the pair — the storage-manager metadata rebuilt until the APFS container inside became mountable, read-only, on the bench. From there the home folder lifted cleanly: the thesis, its LaTeX sources, the datasets, the reference library, and the supervisor correspondence proving which draft was current.
Everything verified and delivered on an encrypted external two days after drop-off — single-drive band despite the two physical devices, because honest pricing follows the job, not the part count. The student’s follow-up email a month later contained one word processors dream of: “Submitted.” The iMac took a clean reinstall on new storage and lived on as the backup machine.
Reinstalling writes over the structures a recovery needs. Power down, bring or post the machine, and the diagnosis is free — £300 + VAT flat if you proceed.