[BUG] Terminal.app crashes during display wake/reconfiguration with fullscreen renderer (TTLogicalScreen NSRangeException)
Preflight Checklist
- [x] I have searched existing issues and did not find this exact crash signature.
- [x] This is a single bug report.
- [x] I am using the latest Claude Code release.
What's Wrong?
Apple Terminal.app intermittently crashes while Claude Code is running with the fullscreen/alternate-screen renderer enabled (CLAUDE_CODE_NO_FLICKER=1). Normal active use is generally stable. The strongest correlation is leaving the session open while the display turns off or the Mac is locked, then waking/unlocking it.
I observed three Terminal.app crashes on the same day. Two occurred about 150 ms after Terminal received display-wake and display-reconfiguration notifications. The third occurred shortly after relaunch during a redraw, with the same internal exception signature.
The process that crashes is Terminal.app, not the Claude Code process. I am reporting this here because:
- the crash happens with Claude Code's fullscreen renderer and virtualized scrollback active;
- switching Claude Code back to the default/inline renderer is an effective mitigation; and
- two Ghostty sessions running the same Claude Code version and renderer at the same time remained stable.
What Should Happen?
Claude Code should redraw cleanly after display sleep, lock-screen wake, or display reconfiguration without causing the host terminal to terminate. If Apple Terminal.app cannot safely support this rendering path, Claude Code should detect it and use the default/inline renderer, or otherwise reset its rendering state before redrawing.
Error Messages/Logs
Sanitized excerpts from the macOS unified log (local time, UTC+08:00):
2026-08-01 08:39:12.102 Terminal kCGSDisplayDidWake
2026-08-01 08:39:12.109 Terminal kCGSDisplayWillReconfigure
2026-08-01 08:39:12.259 Terminal -[TTLogicalScreen expandUnicharOffsetCacheToLine:]: Line 87 out of bounds (87)
2026-08-01 08:41:06.673 Terminal FAULT: NSRangeException
2026-08-01 08:41:06.673 Terminal -[TTLogicalScreen expandUnicharOffsetCacheToLine:]: Line 159 out of bounds (97)
2026-08-01 15:04:28.565 Terminal kCGSDisplayDidWake
2026-08-01 15:04:28.569 Terminal kCGSDisplayWillReconfigure
2026-08-01 15:04:28.681 Terminal invalid display identifier <private>
2026-08-01 15:04:28.708 Terminal -[TTLogicalScreen expandUnicharOffsetCacheToLine:]: Line 161 out of bounds (147)All three .ips crash reports have the same high-level signature:
Exception Type: EXC_BREAKPOINT (SIGTRAP)
Termination: SIGNAL 5, Trace/BPT trap
Faulting thread: 0, com.apple.main-thread
Top frame: +[NSApplication _crashOnException:]
Underlying exception: NSRangeException
Terminal method: -[TTLogicalScreen expandUnicharOffsetCacheToLine:]
CoreFoundation __exceptionPreprocess
libobjc objc_exception_throw
CoreFoundation +[NSException exceptionWithName:reason:userInfo:]
Terminal [private Terminal frames]
AppKit _NSViewDrawRect
AppKit -[NSViewBackingLayer display]
QuartzCore CA::Layer::display_if_neededThe crash reports show only Apple/system images loaded into Terminal.app; I found no evidence of third-party code injection. Full sanitized .ips reports are available if useful.
Steps to Reproduce
This is intermittent, but the following sequence reproduced it multiple times:
- Open Apple Terminal.app.
- Enable Claude Code's fullscreen renderer with
/tui fullscreenorCLAUDE_CODE_NO_FLICKER=1. - Start Claude Code and leave a session open with enough output/scrollback to exercise the TUI.
- Lock the Mac or allow the display to turn off while the session remains open.
- Wake the display and unlock the Mac.
- Terminal.app may crash immediately during redraw/display reconfiguration.
- Relaunching Terminal and resuming use may produce another crash with the same
TTLogicalScreenout-of-bounds exception.
Claude Model
Not sure / multiple models. This appears to be independent of the selected model.
Is this a regression?
I don't know. The default/inline renderer is stable; I have not established a specific last working Claude Code version for fullscreen mode.
Last Working Version
Not established. The old/default renderer is the working configuration.
Claude Code Version
2.1.220 (Claude Code), native installer.
Platform
Other / not relevant to the terminal rendering path.
Operating System
macOS 26.5.2 (25F84), arm64.
Terminal/Shell
Apple Terminal.app 2.15 (470.2), zsh.
Additional Information
Comparison and workaround
- Two Ghostty sessions were running Claude Code 2.1.220 with the same
CLAUDE_CODE_NO_FLICKER=1environment at the time; neither crashed. - Switching Apple Terminal.app sessions to
/tui defaultavoids the problematic rendering path. - The persistent workaround is:
``sh``
unset CLAUDE_CODE_NO_FLICKER
export CLAUDE_CODE_DISABLE_ALTERNATE_SCREEN=1
Hypothesis (not proven)
The immediate exception is in Apple Terminal.app's private TTLogicalScreen implementation. The timing suggests that display wake/reconfiguration invalidates or changes screen geometry while Claude Code's fullscreen renderer is issuing incremental redraw/control sequences against virtualized scrollback. Terminal then appears to draw using a stale line-to-Unicode-offset cache and raises NSRangeException on an out-of-bounds line index.
This could be an Apple Terminal bug exposed by Claude Code rather than a memory-safety bug in Claude Code itself. A Claude-side mitigation could be to default Apple Terminal.app to the inline renderer, or force a clean renderer/state reset after terminal resize, display wake, or geometry changes.
Related reports
- #78650 — Claude sessions crash on macOS wake from deep sleep (different process/signature, same wake boundary)
- #76065 — external-display TUI stays blank until continuous resize/full redraw
- #77615 — overlapping/garbled TUI text and stale cells on macOS
- #80131 —
CLAUDE_CODE_NO_FLICKER=1fails in iTerm2 but works in Ghostty - #72455 — Apple Terminal.app 470.2 fullscreen-renderer compatibility issue;
/tui defaultfixes it
I have intentionally omitted prompt contents, command history, user paths, process IDs, and hardware identifiers from these excerpts.