Is Claude down? › Outage history › Sep 15, 2026
Claude partial outage on Sep 15, 2026: what happened
On Sep 15, 2026, the Claude status page reported "Intermittent error spikes for Claude Mythos 5.1 and Claude Fable 5.1". About 1 hour 26 min: from Sep 15, 2026, 09:48 UTC to Sep 15, 2026, 11:14 UTC, by the official start and resolution times.
Claude right now
At our last refresh (Oct 22, 2026, 12:35 UTC) Claude was up: All Systems Operational.
- Started
- Sep 15, 2026, 09:48 UTC
- Resolved
- Sep 15, 2026, 11:14 UTC
- Duration
- 1 hour 26 min
- Official impact
- Major
- Affected
- claude.ai, Claude API (api.anthropic.com), Claude Code, Claude Cowork
- Source
- Intermittent error spikes for Claude Mythos 5.1 and Claude Fable 5.1 on the Claude status page
The Claude status page rated the impact "Major": a partial outage. Some parts or some users were affected; it was not a complete outage.
What caused the Claude partial outage?
The Claude status page has not published a cause. Its updates describe the symptoms only.
When was it fixed?
The Claude status page marked it resolved at Sep 15, 2026, 11:14 UTC, 1 hour 26 min after it started. A fix was in place and being monitored from Sep 15, 2026, 10:50 UTC. Its resolution note: "A fix has been deployed for Claude Mythos 5.1 and Claude Fable 5.1 and we are monitoring to ensure it has resolved the issue."
Timeline of official updates
Every update the Claude status page posted, oldest first. Times are UTC.
Sep 15, 2026, 09:48 UTC investigating
We are investigating elevated errors on requests to Claude Mythos 5.1 and Claude Fable 5.1. We will provide an update as soon as possible.
Sep 15, 2026, 09:52 UTC investigating
We are investigating elevated errors on requests to Claude Mythos 5.1 and Claude Fable 5.1. We will provide an update as soon as possible.
Sep 15, 2026, 10:50 UTC monitoring
A fix has been deployed for Claude Mythos 5.1 and Claude Fable 5.1 and we are monitoring to ensure it has resolved the issue.
Sep 15, 2026, 11:14 UTC resolved
A fix has been deployed for Claude Mythos 5.1 and Claude Fable 5.1 and we are monitoring to ensure it has resolved the issue.
The same incident was listed for Claude Cowork, Claude Code, which share Claude's status page.
Claude partial outage questions
What caused the Claude partial outage on Sep 15, 2026?
The Claude status page has not published a cause.
When was the Claude partial outage on Sep 15, 2026 fixed?
The Claude status page marked it resolved at Sep 15, 2026, 11:14 UTC, 1 hour 26 min after it started. A fix was in place and being monitored from Sep 15, 2026, 10:50 UTC. Its resolution note: "A fix has been deployed for Claude Mythos 5.1 and Claude Fable 5.1 and we are monitoring to ensure it has resolved the issue."
How long did the Claude partial outage last?
About 1 hour 26 min: from Sep 15, 2026, 09:48 UTC to Sep 15, 2026, 11:14 UTC, by the official start and resolution times.
Was Claude completely down?
No. The Claude status page rated the impact "Major": a partial outage. Some parts or some users were affected; it was not a complete outage. The affected parts listed were: claude.ai, Claude API (api.anthropic.com), Claude Code, Claude Cowork.
Which parts of Claude were affected?
The Claude status page listed: claude.ai, Claude API (api.anthropic.com), Claude Code, Claude Cowork.
Other recent Claude incidents
- Elevated errors affecting Connectors Oct 22, 2026, 03:50 UTC, 4 hours 17 min
- Degraded performance for Claude Fable 5 Oct 21, 2026, 19:49 UTC, 40 minutes
- Issue with spend limits Oct 7, 2026, 21:23 UTC, duration not stated
- Elevated errors on platform.claude.com Oct 7, 2026, 13:25 UTC, 6 days 5 hours
- Elevated errors loading usage data on platform.claude.com Oct 7, 2026, 01:20 UTC, 1 hour 13 min
- Elevated errors for Claude Opus 5.5 Oct 6, 2026, 12:24 UTC, 19 minutes
Full Claude outage history and biggest outages → · Recent outages across all services →
Quotes are the Claude status page's own words, from the official incident. Is It Up or Down is independent and not affiliated with Claude. Times are UTC.