Apparent Zcash outage was a block explorer problem, infrastructure provider says

• The Zcash blockchain supposedly stopped producing new blocks for more than four hours on Wednesday.
• One expert, however, said that the issue was mainly with block explorers tracking the activity rather than the blockchain itself.

For a few hours Wednesday Asia time, Zcash's blockchain appeared not to be producing any new blocks — but that's an issue with the block explorers themselves, not the chain, per some observers.

Think of the blockchain as a ledger that keeps growing as new transactions are added. Each “block” is a new entry in the ledger. So, when the network stops making new blocks, no new transactions can be confirmed. This is like the entire payment system freezing for several hours.

According to multiple Zcash block explorers, the most recent block was number 3,364,601, created at 5:27 AM UTC on June 3. After that, no new blocks appeared for over four hours. Normally, Zcash adds a new block roughly every 75 seconds (just over a minute).

However, the Zcash blockchain was not down. The problem was that some of the block explorers didn't update their nodes after the recent network upgrade.

"A coordinated Zcash network upgrade was activated at block 3364600. Many block explorers had not yet updated their nodes at the time of the upgrade, resulting in a loss of visibility into the chain's state," CEO of ZODL Josh Swihart told CoinDesk.

"In simpler terms, a network upgrade is a 'hard fork' of the chain. The miners started producing blocks on the new chain, leaving the old one behind, but many popular block explorers were still watching the old one," Swihart added.

Mert Mumtaz, CEO of Helius, an infrastructure provider to Solana, also echoed Swihart's explanation behind the incident.

He said this is an issue with some block explorers not updating their nodes since the network upgrade this week, and that they are working on updates now.

Zcash's native token ZEC has surged 8% over the past week, according to CoinDesk data, bucking the broader market weakness. The token has gained 46% in the last month.

For crypto investors, this event is a reminder that even well-known networks can run into technical hiccups.

UPDATE (June 3, 18:17 UTC): Adds comments from Josh Swihart.

UPDATE (June 3, 11:00 UTC:) Updates title and text to say the issue may have been with the block explorers.

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