Around 30 people in Ipswich received double the money they requested from a Lloyds Bank cashpoint in Ipswich on Tuesday evening.
The incident happened in Nacton Road and led to a large crowd gathering as people became aware of the potential windfall.
Police had to be called until staff from the bank arrived to turn the machine off.
A police spokesman said: "The incorrect dispensing of cash is not a police issue, but we remained on the scene until staff from the bank arrived."
The bank said that the situation only lasted for a short period and it was unlikely to try and recover the windfall that an estimated 30 people received.
A spokesperson for Lloyds TSB said: "For a very short period of time, the ATM was mis-dispensing cash while the branch was closed.
"It's quite difficult to trace all the payments, because they won't all be our customers, so it's unlikely we will take any action.
"We apologise for any inconvenience caused."
One Twitter user, @FizzySparkler, commented: "Nice to see one bank is giving back."