What happens if I never run a fixity check on my preserved digital records?

A fixity check verifies that a digital file has not changed since it was captured or last verified. It works by generating a checksum (a unique digital fingerprint, such as an MD5 or SHA hash) and comparing it against the value recorded earlier. If the two match, the file is intact. If they differ, something has altered the bits. Skipping this step does not make your records safer; it simply removes your ability to know whether they are still trustworthy.

What can go wrong silently

Digital storage is not permanent in the way many assume. Over time, files can degrade or change without any obvious warning through:

• Bit rot — gradual decay of storage media that flips or drops individual bits.
• Hardware and transfer errors — faults during copying, migration, or backup.
• Software or system failures — incomplete writes, corrupted indexes, or storage bugs.
• Undetected tampering — unauthorized edits that leave no visible trace.

Without periodic fixity checks, this damage accumulates quietly. By the time a corrupted file is finally opened, the original may be long gone and unrecoverable.

Why it matters for records

Preservation is not just about keeping a file; it is about keeping a file you can rely on. Records management standards emphasize that records must remain authentic, reliable, and usable for as long as they are retained. Fixity is one of the core controls that supports those qualities.

If you never run fixity checks, you risk:

• Loss of integrity — you cannot demonstrate that a record is unchanged from its original state.
• Loss of authenticity — you cannot prove the record is what it claims to be, which can undermine its value as evidence.
• Loss of trust — auditors, courts, FOIA requesters, or researchers may reasonably question records that lack documented integrity controls.
• Irreversible loss — corruption discovered too late often cannot be fixed.

Good practice

Run fixity checks on a regular schedule, log the results, and keep at least one verified copy in separate storage so a damaged file can be replaced from a known-good source. Documenting these checks creates an audit trail that shows your records have been actively maintained, not merely stored and forgotten.

To explore related topics, see the archives and preservation hub.