When a file is deleted, the data usually isn't wiped immediately — the space it occupied is just marked as available to be overwritten. Recovery software works by scanning for that not-yet-overwritten data before something else claims the space.
Stop using the drive immediately once you realize you need to recover something. Every new file saved, every temp file written by normal computer use, is a chance to overwrite the exact sectors your deleted file occupies. Recovery software installed and run after the fact from the same drive can itself overwrite what you're trying to recover — running recovery software from a different drive, or at minimum not saving new files to the affected drive, meaningfully improves your odds.
It scans the drive at a low level for file signatures and directory remnants that the operating system no longer shows you, then lets you preview and selectively restore what it finds — success rates vary heavily by how much has happened on the drive since deletion, not by which specific tool you use.
Because recovery odds are dictated mostly by how much new data has been written since deletion, comparing recovery tools on marketed "success rate" claims is largely beside the point — nearly any competent recovery tool will find a file deleted five minutes ago on an otherwise idle drive, and none will reliably recover a file whose sectors have already been overwritten by days of normal use. The urgency is in stopping drive activity, not in researching which specific product to buy.
Physically damaged drives, or data that's been genuinely overwritten by substantial new disk activity, generally can't be recovered by software alone — at that point professional data recovery services (which work at the hardware level) are the only realistic option, and they're worth the cost only for data that's genuinely irreplaceable.
The entire recovery scramble is avoidable with a working backup already in place — this scenario is exactly the argument for maintaining actual versioned backups rather than relying on sync alone, since a deleted file recovered from a backup snapshot is instant and certain, compared to the uncertain, time-pressured process of attempting data recovery after the fact.
Free recovery tools are often genuinely adequate for straightforward, recently-deleted files on a healthy drive — the underlying scanning technique isn't dramatically different between free and paid options for this common case. Paid tools tend to differentiate on deeper scanning for more damaged file systems, support for a wider range of storage formats, and customer support if something goes wrong, which matters more for a business-critical recovery than a personal file.
Anyone who's gone through a stressful deleted-file recovery scramble once tends to become far more diligent about backups afterward — worth treating that lesson as an opportunity to actually set up automatic backups now, rather than only remembering the fear the next time a file goes missing without one in place.
