Take a moment to consider this: Whether data is stored magnetically on spinning magnetic discs, or electrostatic charges in SSDs and other flash media, mass storage devices have no way of determining how well data that was once written can still be read today unless they are asked to do so. It is only when a mass storage device is asked to read its data that it's able to discover whether or not that data is readable – and how quickly & easily. Until then, it must be taken on faith.
SpinRite rapidly scans spinning or solid-state mass storage media to verify, restore, repair and improve its current readability. If anything is found to be amiss, SpinRite's legendary data recovery technology gets to work, often pulling unreadable or barely readable data back from the brink. If this seems difficult to believe, how many thousands of testimonials would you care to read from past SpinRite users?
Once the endangered data has been recovered to the best of SpinRite's ability (which far exceeds any other known utility), what SpinRite recovered will be rewritten, possibly into a new location on the media for safe keeping and trouble-free reading when it is needed.