Failure to reach a consensus explains six-hour shutdown of the Swiss network.

• Failure to reach a consensus paralyzed Sui's mainnet for six hours.
• Validators interrupted the network to prevent inconsistent state.
• The correction restored operations without impacting funds.

SUI released a post-incident report clarifying the causes of the disruption recorded on its main network on January 14, 2026. The outage lasted approximately six hours and temporarily affected transaction execution and checkpoint certification across the blockchain.

The problem originated from a disagreement in consensus among validators. The SUI (Superintendency of the Securities and Exchange Commission) emphasized that the failure was not related to network usage spikes, external attacks, or security incidents. Throughout the entire period, user funds remained protected, without any reversal of already certified transactions.

The report details that a specific bug in the processing of consensus commits led different validators to distinct interpretations when dealing with certain conflicting transactions. This resulted in the generation of divergent checkpoint candidates, preventing the achievement of the participation-weighted consensus necessary to advance the network state.

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Upon identifying that a significant portion of the validators were signing inconsistent checkpoint data, Sui's security mechanisms were automatically triggered. The network was deliberately interrupted to prevent an inconsistent state from being finalized, even if this meant temporarily suspending block production.

During the downtime, the sending of new transactions timed out, but read-only queries remained available, allowing access to the last certified endpoint. It is estimated that approximately US$1 billion in on-chain value remained inactive while the mainnet was down, with no forks or operational losses occurring.

Recovery began as soon as the root cause was identified. Validators removed the incorrect consensus data, applied a correction to the confirmation logic, and reproduced the chain from the exact point of divergence. After initial testing with a canary protocol conducted by Mysten Labs validators, the broader set of participants updated their systems.

With the resumption of checkpoint signatures, the network returned to normal operation on the same day. The Sui team stated that the episode demonstrated the project's focus on prioritizing blockchain state consistency, even at the expense of uptime in critical situations.

In response to the incident, improvements are planned for validator automation processes, expansion of testing to capture extreme consensus cases before production deployment, and mechanisms for earlier detection of inconsistencies. The January 14 outage marked the second significant failure of SUI since its launch in 2023, following a smaller episode in late 2024, while the behavior of the SUI token indicated limited volatility during the event.