GitHub issue #57580 in anthropics/claude-code, opened 2026-05-09 by JDL747, records a report that long Bash-heavy Claude Code Desktop sessions accumulate PTY master file descriptors against /dev/ptmx until macOS's kern.tty.ptmx_max (511) is exhausted, after which forkpty(3)/posix_openpt(3) fail with ENXIO for every process on the machine; the reporter notes that quitting and relaunching Claude releases the descriptors.
Verbatim Excerpts from Cited Records
“After a long Claude Code session that issued many Bash tool calls, the Claude desktop process accumulated 511 open file descriptors against `/dev/ptmx`, exactly matching `kern.tty.ptmx_max=511`.”
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anthropics/claude-code (issue 57580 opening body, Summary paragraph)
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2026-05-09T10:35:40Z
·GitHub Issue ↗
“From that point on, `forkpty(3)` and `posix_openpt(3)` fail with **errno 6 (ENXIO, "Device not configured")** for every process on the machine, not just inside Claude.”
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anthropics/claude-code (issue 57580 opening body, Summary paragraph)
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2026-05-09T10:35:40Z
·GitHub Issue ↗
“The workaround is to quit and relaunch Claude.”
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anthropics/claude-code (issue 57580 opening body, Summary paragraph)
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2026-05-09T10:35:40Z
·GitHub Issue ↗
Counter-record: No in-thread refutation as of 2026-10-02: ~20 comments corroborate with independent measurements (506/511, 501/511, 508/511 held FDs). github-actions bot flagged possible duplicate #47909 on 2026-05-09, but issue #57580 was closed as completed (not as duplicate) on 2026-06-22.
Falsification probe: If issue #57580 is deleted without archive, or the author edits the opening body so the quoted sentences no longer match verbatim, this claim drops to Withdrawn.
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