A Wells Fargo glitch drained some customer accounts by double-paying their bills online.
The bank apologized on Thursday for its latest embarrassment and said the "error" was fixed overnight. Wells Fargo promised to refund any related fees or charges.
It declined to say how many customers were affected.
Some furious customers blasted the bank on Twitter. They said they had to frantically call the bank for help after their accounts were overdrawn.
Wells Fargo said the glitch was caused by an "internal processing error" that caused "temporary double posting of some items."
The bank is still trying to shake a year of scandal, mostly about mistreating customers and workers.
Wells Fargo has admitted that its workers responded to wildly unrealistic sales goals by creating 3.5 million potentially fake accounts. The bank has also said it forced up to 570,000 customers into unneeded auto insurance.
Wells Fargo has repeatedly apologized. It has also replaced its controversial sales goals and installed new management.
Even though Wells Fargo is among the biggest winners from the federal tax overhaul, the bank announced plans last week to close 800 more branches by 2020. Analysts say the branch shutdowns are an effort to cut costs as the bank faces surging legal expenses.
Wells Fargo said closing branches is a logical response to Americans' increasing preference for online and mobile banking.