Data blocking is not a strict technical standard term. In incident reports, it usually means some kind of interference that prevents people or systems from accessing, moving, or using data. Depending on context, it could describe blocked reads and writes, interrupted transfers, denied permissions, storage disruption, or a broader service outage.
In cyber security, the term matters because it is often used loosely in attacker claims and victim listings. A label like this does not by itself prove encryption, exfiltration, or a full compromise. Defenders should verify the real effect with logs, authentication events, file-system alerts, and network telemetry. In practice, “data blocking” may appear in ransomware, extortion, misconfiguration, or defensive controls such as access rules and content filters, where the goal is to prevent unauthorized use or movement of sensitive information.