Numerous Google Docs users have reported that they are being mysteriously locked out of certain files in their accounts.
The error causes files to be flagged as violating Google’s terms of service.
Users received a message saying: “This item has been flagged as inappropriate and can no longer be shared.”
“We’re investigating reports of an issue with Google Docs,” a spokesman told the BBC. “We will provide more information when appropriate.”
Users have taken to Twitter to complain about the issue, saying that while they were working on documents the screen suddenly froze, and then a message came up telling them they could no longer access a file.
Some people have also reported that another error prevented them from sending Google appeal requests to unlock their files.
Other strange behaviour has been noticed on the service – one user, Iain Mackenzie, said the words “game is over” had flashed up in a Google Docs document he had been editing and then disappeared.
Mr Mackenzie said that no other user had been in the file at the time, and that the Google Docs revisions log showed only he had been editing the document for the past few hours.