The problem reportedly started on 12 August when a worker at the Rocky Mountain Bank sent an email containing the names, addresses, social security numbers and loan data of more than 1300 customers to the random Gmail address.
When the employee realized the mistake, a second email was sent to the Gmail account requesting that the recipient contact the bank and destroy the data.
On investigation, Google told the bank that it must get a court order to gain access to the email account, and last week a San Jose judge ordered Google to deactivate the Gmail account.
A spokesperson for Google, Amy Pederson, told the CNET newswire that, after notifying the Gmail account owner, Google complied with the court's order.
"While we regret that the user has been locked out of their account through no fault of their own, we're not legally able to reactivate the account until the court approves our motion to dismiss the case", she said.
"We're hopeful that the court will act quickly, and as soon as the motion is approved, we'll reactivate the account."
Infosecurity notes that the saga has potentially profound implications for users of the Gmail email service, which is provided free of charge to more than 140 million users worldwide.
In one of its email terms and conditions, the free Gmail service operator states: "You agree that this licence includes a right for Google to make such content available to other companies, organizations or individuals with whom Google has relationships for the provision of syndicated services, and to use such Content in connection with the provision of those services."