A fundamental data protection principle in LogScale that ensures ingested data cannot be modified or edited after it is stored. Once events are written to a repository, they remain in their original state, providing a trustworthy and tamper-proof record for security analysis, compliance auditing, and forensic investigations. This immutable architecture prevents both accidental modifications and malicious tampering, making LogScale particularly valuable for regulatory compliance requirements that demand verifiable audit trails. Data can only be removed through controlled deletion methods with specific elevated privileges: automatic purging based on retention policies, manual repository deletion by authorized administrators, or targeted redaction through the API. Immutability works in conjunction with encryption at rest and checksums to provide comprehensive data integrity protection.