Outage in Anthropic

Claude Code showing "JSON Parse error: Unexpected EOF" and writing excessive files on Windows

Resolved Minor

February 26, 2026 - Started about 11 hours ago - Lasted about 3 hours
Official incident page

Incident Report

Summary AI Generated

Claude Code version 2.1.59 introduced a bug causing Windows users to experience "JSON Parse error: Unexpected EOF" messages and excessive file writes due to write contention issues with the .claude.json global config file. The issue affected Windows users for 3.2 hours and was resolved with the release of version 2.1.61, which users could obtain by running `claude update`.

We have identified a bug where Windows users are experiencing significant write contention for the .claude.json global config file, starting with Claude Code 2.1.59. We are working on a hotfix.

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Latest Updates ( sorted recent to last )

RESOLVED about 8 hours ago - at 02/26/2026 11:07PM

We've confirmed this issue is resolved in Claude Code v2.1.61. Run `claude update` for the latest.

MONITORING about 8 hours ago - at 02/26/2026 10:43PM

We have deployed a fix to this issue in version 2.1.61. Run `claude update` to get the latest version.

We are monitoring for config corruption rates in this version since it is a nondeterministic, environment-dependent failure.

IDENTIFIED about 10 hours ago - at 02/26/2026 09:06PM

We are continuing to work on deploying a hotfix for this issue.

IDENTIFIED about 11 hours ago - at 02/26/2026 07:57PM

We have identified a bug where Windows users are experiencing significant write contention for the .claude.json global config file, starting with Claude Code 2.1.59. We are working on a hotfix.

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