No One Reads Beneath an Overwrite

The decode

A reinstall does not erase a drive; the years of use afterwards do. Installing a new operating system overwrites some areas and marks the rest as free. Every day of use since then has been quietly taking up that free space. A file from before the reinstall survives only where nothing has landed on its sectors in all the time between, and each passing year shortens those odds.

The tools he bought weren't failing; they were reporting. Commercial recovery software carves free space looking for recognisable file signatures. That they recovered "quite a bit" but never the wallet shows the search worked and the target wasn't in the reachable remainder, or survives only in fragments too small to announce themselves. More tools of the same kind just repeat the same sweep.

"How deep" deserves a straight answer. Writing new data over a sector removes the previous contents, and as a matter of physics (not salesmanship) those old bytes are gone; there is no deeper layer where they wait. Any service which claims to recover data from beneath an overwritten sector is simply selling something that doesn't exist. What a lab can legitimately add is completeness: a full byte-level sweep of every unallocated area of the write-blocked image, targeted at the wallet file's own internal signatures rather than generic data types. A lab should also be honest with the client about exactly what the sweep shows.

The kind of drive decides how much hope is rational. If this MacBook contains a hard disk drive, overwritten means overwritten, but untouched regions can genuinely remain intact for years, so a targeted sweep for the wallet's internal signatures has a real if modest chance. If it uses a solid-state drive, the housekeeping that keeps an SSD fast cleans up discarded space in the background, usually within days of the reinstall, which happened years ago. Whether it is an HDD or an SSD is established in the first minutes of assessment and shapes everything said after that.

The most promising search may not be on this drive at all. A wallet file is small and travels: old external backups, a Time Machine disk used even once, a previous computer, an email sent to oneself. Sideways is where files lost to time most often turn up — and it costs nothing to look there while the sweep runs.

On success rates, the defensible number is conditional. Across this class of work, recoveries come from surviving unallocated fragments or from lateral copies; they do not come from beneath overwrites. Anyone quoting a confident blanket percentage for a years-old deletion is quoting marketing, not evidence.

On the bench

The medium was identified first, since disk and SSD set different expectations. The image was taken under a Tableau hardware write-blocker, its unallocated space swept end to end in X-Ways Forensics for the wallet file's database signature values, candidate fragments hex-verified rather than trusted by name and cross-checked with OSForensics, and the result reported against the whole sweep — including, where that is the truth, that the sectors in question have been reused and the file no longer exists to find.

The outcome

Write-blocked image, medium established, full unallocated sweep for the file's own signatures, hex-verified findings, and a parallel checklist of lateral sources. Free assessment, one fixed written figure, plus VAT; where recovery is not possible, nothing is charged. The decode: depth is not the variable — survival is. We search everything that still exists and tell you plainly which category your file fell into, because a paid-for maybe is worse than an honest no.

Our case files are written up from genuine enquiries our lab has handled for customers across Sheffield and South Yorkshire, anonymised to protect client confidentiality. Each one describes the diagnostic and recovery approach our engineers apply to that fault, using the equipment listed.