Harmony Shuts Down Mainnet, Migrates ONE Token to Ethereum

Harmony's mainnet is shutting down on September 6, 2026, after being launched in 2019. The team behind the network has announced that it will reissue the ONE token as an ERC-20 token on Ethereum. This change affects all holders of ONE, and it's essential to understand what this means for your tokens.

The mainnet shutdown is a result of a cross-shard exploit that occurred on August 12, 2026. The attack resulted in the creation of approximately 3.01 trillion forged ONE tokens, accounting for around 26% of the total supply. To mitigate this issue, Harmony opted to rollback the chain to a state before the attack.

The shutdown affects all addresses holding ONE in smart contracts, such as liquidity pools, multisig wallets, and DeFi positions. These balances will not be transferred during the migration process. However, if your ONE is stored in an ordinary wallet or on an exchange, it will be captured by a snapshot and credited again on Ethereum without any additional action required.

Holders are advised to exit all smart contracts before September 10, 2026, as positions within these contracts will not be migrated. The team has stated that the threats posed by state actors and AI agents are too great for Harmony to continue operating its own chain.