ChatGPT has gone offline in a major outage.

Visitors to OpenAI’s chatbot saw an array of strange behaviour – including the site attempting to download an unusual file.

Users joked that the outage meant they would have to use their own brains at work. But it also led to an array of problems across other sites and apps, many of which rely on OpenAI for their artificially intelligent features.

OpenAI said it was aware of the problem, had found a way to fix it and was currently looking to understand whether it had worked. Shortly after, however, it said that it was “still experiencing degraded performance”.

The problem was also affecting Codex, OpenAI’s tool to use ChatGPT for programming.

Some users reported similar problems at other rival chatbots, such as Anthropic’s Claude and X’s Grok. But those appeared to be at least more minor in their scope, and continued to work for many visitors.