A Claude outage disrupted Claude.ai, Claude Code, Claude Cowork and API services on September 29, 2026. More than 11,000 U.S. users reported problems as Anthropic investigated elevated errors before most services recovered within about an hour.
Anthropic’s Claude experienced a widespread service disruption on Tuesday, September 29, 2026, affecting its chatbot, developer tools and API before services recovered later in the morning.
More than 11,000 U.S. users had reported Claude problems to Downdetector by 10:12 a.m. ET, according to Reuters. Anthropic acknowledged elevated error rates across Claude services and began investigating the disruption.
Claude.ai and developer services affected
Anthropic’s incident updates showed that the disruption affected Claude.ai, including its desktop and mobile apps, as well as Claude Code and Claude Cowork.
Some Claude API requests were also returning errors. Users could encounter failed requests, problems loading or sending conversations, or prompts to sign in again.
The incident was first formally listed by Anthropic at 14:21 UTC, or 10:21 a.m. ET, although the company later said the impact had begun around 14:00 UTC.
Sign-in and new chat problems continue after initial mitigation
Anthropic applied a mitigation as the incident developed, substantially reducing error rates. However, some problems persisted after the initial improvement.
Sign-ins, account actions and some Claude Code and Cowork sessions continued to fail for certain users. Other reported problems included starting new conversations, voice conversations, purchases and file uploads.
Most Claude services recover within an hour
Anthropic reported that most services had recovered by 14:59 UTC, or 10:59 a.m. ET.
Sign-ins, new chats, voice conversations, Claude Code and Cowork sessions, purchases and file uploads were working again as the company moved the incident into monitoring.
Anthropic also warned that some messages sent during the disruption window may not have been saved.
The company later marked the incident resolved, with the main impact occurring from approximately 14:00 UTC to 14:59 UTC.
Cause of Claude outage not disclosed
Anthropic did not publicly identify a technical cause for the September 29 disruption in its initial incident updates.
The outage affected both consumer-facing Claude services and tools used by developers, making the API and Claude Code disruptions particularly relevant for businesses and software products that rely on Anthropic’s platform.
Claude’s official status page subsequently showed its main services as operational.
