Claude (Anthropic) outage on September 10, 2026: Degraded functionality for Claude Cowork on Windows
Claude reported an incident affecting Claude (Anthropic) for 4 days 3 hours on 10 September 2026, from 15:54 to 19:14 UTC.
Resolved
Official incident reported by Claude
- Started
- 15:54
- 10 Sep 2026 UTC
- Resolved
- 19:14
- 14 Sep 2026 UTC
- Duration
- 4d 3h
- 4 days 3 hours
- Impact
- Major
- as rated by Claude
- Updates
- 2
- posted by Claude
Timeline
All times UTC.
Official incident from Claude
Degraded functionality for Claude Cowork on Windows
-
Official
Identified
A Windows update released September 8 has left Claude Cowork on Windows unable to run local commands, because its workspace can no longer reach your computer's drive. For most users, chat and file reading and editing still work. There's no in-app workaround yet, and restarting or reinstalling won't help. Microsoft has developed a fix and is working to release it. We'll post an update when we have more to share.
-
Official
Resolved
This issue has been resolved. Microsoft has released a September 14 Windows update that fixes it: https://support.microsoft.com/en-us/servicing/os/windows-11/2026/09/kb5129195-windows-11-24h2-25h2-security-update
"Official" rows are quoted from Claude's public status page, status.claude.com. Very long posts are shortened.
What our checkpoints saw
HostTracker's checkpoints, which test claude.ai from several locations, recorded no outage of 5 minutes or longer during this incident. A provider can report a problem that affects only some features, regions or accounts, which a check of the main address does not see. The live Claude (Anthropic) status shows what our checks see right now.
Does your product depend on Claude (Anthropic)?
An outage like this one reaches your users through your product, and most teams hear about it from a customer rather than from a dashboard. HostTracker watches any endpoint you name - your own site, an API you call, a vendor you resell - from 300+ locations, confirms a failure from several of them before it says anything, and then tells you by email, SMS, voice call or your chat tool.
You get the same record you are reading here for your own services: every outage timestamped, with the checks that observed it.
Independent measurement by HostTracker. Not affiliated with Claude (Anthropic). Official updates are quoted from Claude's public status page and remain Claude's own words.