06/17/2026
What Immutable Backup Means
Ever had to fill out a cyber insurance application and stared at a question like this one?
"Do you maintain immutable, air-gapped, or offline backups of your critical business data?"
Most small business owners check yes.
They have backups, the backups run every night, and someone is paid to handle them. That seems like a yes.
But the question is asking something more specific. If a hacker had your admin password right now, could they delete your backups before you noticed?
A backup on the same network as the rest of your systems, controlled by the same admin account, doesn't pass that test.
The same goes for Microsoft 365's native retention and for most cloud backup setups where the immutability switch was available but nobody turned it on.
Why it matters: checking yes when the honest answer is no can trigger rescission after a claim, which means the carrier treats the policy like it never existed. Coverage gone.
We wrote up what immutable backup means in plain English, three questions to send to your IT provider before you sign the form, and what to do if your honest answer is no.
https://onwardcs.com/news/what-immutable-backup-means-on-your-cyber-insurance-form/
