Sui's blockchain went dark for nearly six hours yesterday, May 28, after a bug in its latest software upgrade halted all block production. The disruption lasted exactly 5 hours and 55 minutes, making it the second major downtime event for the network this year.
What went wrong
The cause was a bug in the 1.72 upgrade. Validators stopped producing blocks shortly after the update went live. The Sui team didn't immediately detail the exact code issue, but the network came back online after the bug was identified and patched.
The recovery
Block production resumed after nearly six hours of silence. During the stall, transactions were queued and smart contracts couldn't execute. Users on Sui-based apps saw frozen balances and pending transactions. The network eventually caught up and processed the backlog.
A familiar problem
This isn't Sui's first major outage in 2026. Earlier this year, the network suffered another significant downtime event. Two stoppages in six months raise questions about the chain's upgrade process and overall reliability — especially for DeFi protocols that depend on uninterrupted block production.
