Thousands of Gmail users have been left with empty inboxes after their accounts were accidentally wiped clean.
As well as missing e-mails, many reported that their contacts had also disappeared.
In a statement, Google said: "This is affecting less than .08% of our Gmail user base, and we've already fixed the problem for some individuals."
The company said that engineers were working to restore service.
Google does not release official figures for the number of Gmail accounts, however it is believed to be between 150 million and 200 million.
That would mean that around 150,000 users were affected by the problem.