Model behaviour issues on Windows — page 3
Issues the maintainers labelled both platform:windows and area:model.
1,301 issues · 469 open · 832 resolved (64%) · first seen May 31, 2025
Is this getting better or worse?
This class of problem is still growing. 671 new reports in the last 90 days vs 358 in the 90 before — +87%. The open backlog peaked at 469 in 2026-10 and sits at 469 today.
Derived by counting each matching issue from its creation date until it closed. First-party
computation over the anthropics/claude-code tracker — the trend is not published
anywhere upstream.
Which builds report this
901 of these reports name the Claude Code build they were running, spanning 180 releases. Heaviest reporters:
- Claude Code v2.1.289
- Claude Code v2.1.296
- Claude Code v2.1.280
- Claude Code v2.1.233
- Claude Code v2.1.71
- Claude Code v2.1.278
- Claude Code v2.1.237
- Claude Code v2.1.119
Report volume, not a defect count: an issue can mention a build without that build having caused the failure. Versions come from the version string in the bug-report template, matched against real published tags.
Do these get fixed?
Median time to close is 36 days across 832 closures. Of the 832 closures with a recorded reason, 10% were closed as completed and 749 as not-planned or duplicate. The most recent completed fix landed in 2026-10.
Workarounds reported by the community
120 of these issues post a workaround someone says worked. The highest-engagement ones:
- [BUG] Advisor always "unavailable" with Fable 5 advisor (Opus 4.8 main) across all sessions (v2.1.198)
- Right now, my workaround is just launching a Fable 5 agent. Not ideal since seamless handoff is preferred, but it works. Does anyone know if the advisor mechanism actually saves on Fable 5 tokens, considering how differe…
Found in the thread of #73365 · resolved - Recurring error: "The model's tool call could not be parsed (retry also failed)" interrupts sessions
- Workaround: use an English or French session instead of Chinese / Japanese First-person data point supporting the non-ASCII trigger suspected here: I kept hitting while working in Chinese . Opened a new session in French…
Found in the thread of #63875 · resolved - [BUG] Can't see Claude's thinking anymore
- …problem as you. Looking through other issues, I found this workaround: Hopefully they fix it in general soon. In many cases, Claude is unusable when the thinking is not displayed. It runs for minutes, burns tokens, and…
Found in the thread of #24285 · still open - Subagent model routing is broken — all mechanisms resolve to parent model (Opus)
- …pe), which the changelog doesn't mention. The full-model-ID workaround noted above likely still applies there.
Found in the thread of #43869 · still open - Hard block on typing passwords breaks legitimate dev/test workflows - needs a permission-gated opt-in for own dev environments
- …rver-side and dies on every app restart. Claude's suggested workaround was exactly that, and it collapsed on first contact with reality. We ended up building a passwordless dev-auto-login endpoint into the app (gated to…
Found in the description of #78160 · still open
Excerpts are quoted from the linked issue so you can judge relevance before opening it. Threads that only ask for a workaround, or report that there is none, are excluded. These are community suggestions, not official guidance from Anthropic — read the full thread before applying one.
Matching issues 201–300
Ranked by community engagement (reactions weighted over comments). Listing the top 300 of 1,301 matches; the statistics above cover all 1,301.
- [Bug] Claude Code not following skill instructions
- [BUG] Claude ignores its own memory instructions repeatedly — behavioral rule enforcement failure
- [BUG] Plan mode violated after ultraplan approval, model edits source files instead of plan file
- [Bug] Performance degradation during night hours (EU region)
- [Bug] Claude ignores non-fatal tool output — warnings and stderr treated as success
- [Bug] Verification queries are tautological — cannot return failure results
- [BUG] VS Codium extension ignores model configuration and defaults to Opus 4.1
- [BUG] /model command shows Opus as "Default" instead of "Opus"
- [BUG] Haiku always runs upon any client init
- [Bug] Anthropic API: Opus Model Functionality Discrepancy Between CLI and Web Interface
- [Bug] Manual password input required for UI testing breaks automated workflows
- [Bug] Fable 5.1 incorrectly blocked by usage credits despite included Max plan allowance
- Fable 5.1 repeatedly ignores a standing "read the record before acting" directive (13 recorded instances in 15 days)
- frequesnt and invalid Fable 5's safeguards flag
- [Bug] Claude Code ignores conciseness instructions and over-elaborates responses
- [Bug] Sonnet 5 deletes entire folder contents while attempting file enumeration
- claude-opus-4-8: malformed tool-call wrapper (raw <invoke> XML leaks as text, tool call fails) + off-topic/hallucinated replies since ~2026-06-26
- [BUG] Opus 4.8 frequently enters long "thinking" on simple tasks without taking action — suspected regression
- [BUG] Claude is not available - Money or compensation!
- [BUG] Claude Code repeatedly fails to follow CLAUDE.md session branch + push discipline
- Opus 4.6: Poor instruction adherence and context retention in long sessions
- [MODEL] Korean output corruption — words replaced with "영역" token in long responses
- [BUG] Cross-session blindness causes three-stage failure: incomplete refactor → misdiagnosis → unauthorized revert
- [BUG] Claude Code repeatedly generates invalid tool invocations
- Claude not following instructions and jumping rails.
- [Bug] Context display shows incorrect token estimates for Opus 4.7 model
- Opus 4.7 regression: weaker keyboard-language typo detection + less precise memory/MD file writes vs Opus 4.6
- [BUG] Error: Extra usage is required for 1M context · run /extra-usage to enable, or /model to switch to standard context
- [Bug] 1M context window not auto-applied on Max plan in Claude Code CLI v2.1.114 (plus: `--model` flag silently drops `[1m]` suffix)
- Model skips mandatory CLAUDE.md session-start instructions when task context is present
- [MODEL] Claude repeatedly takes unauthorized server actions and fabricates data despite 41 documented corrections
- [Feature Request] AskUserQuestion usage declining with system prompts
- [MODEL] Claude Code stopped delegating to custom subagents and loading skills — regression persists in Opus 4.6
- [BUG] `context: fork` and subagents appear to use a different (lighter) model despite model configuration
- [BUG] Claude Code Caused Production Server Outage and Data Loss
- Claude recreates existing files from scratch after session compaction — CLAUDE.md instructions ignored
- Opus 4.6 (1M): Ignores CLAUDE.md rules and user instructions in long sessions
- [Bug] Reasoning model failing consistently at night
- Claude Code refuses direct user requests to file GitHub issues about its own failures
- [BUG] Edit tool gets stuck targeting wrong file in a loop (path contamination)
- [BUG] sudden nonsense responses all over the CLI version.
- [BUG] Claude Code systematically ignores rules from memory/CLAUDE.md on every edit/write
- Claude Code destroyed gitignored files with unnecessary git clean -fd during branch creation
- [Bug] Anthropic API Error: Invalid thinking parameter in requests
- [Bug] Degraded Code Generation Accuracy and Instruction Following
- [Bug] Sonnet 4 Model Consistently Introduces Non-Standard Code Patterns
- [Bug] Opus Model Access Blocked Despite MAX 20x Plan Subscription
- [BUG] Opus 4.1 model is not using MCP servers
- Unhandled Anthropic API Response Containing Inappropriate Language
- [Bug] Claude Code consumes credits and produces unwanted output despite user instructions
- [Bug] False-positive reasoning_extraction safety blocks interrupt Claude Code sessions
- [BUG] Tarea incompleta, bloqueos M365/auto-mode confusos y trato despectivo al usuario
- Hanja/foreign character substitution recurs in normal chat responses, not just suggestion box
- [Bug] Fable 5 fallback to Opus 4.8 preserves effort level instead of mapping to capability-equivalent tier
- Python file I/O snippets should always include encoding='utf-8' to prevent silent data corruption on Windows (follow-up to #62828)
- [BUG] Claude Code wastes paid sessions fixing self-created bugs — no accountability, no forward progress
- [BUG] /model does not display sonnet[1m] or opus[1m] despite both models being accessible via --model
- [MODEL] Claude Code safe-mode --print/resume misroutes conceptual prompt as tool-task clarification
- [MODEL] Opus 4.8 convinced me I was under a prompt injection attack .It startled me. After repeated verification, it turned out to be an illusion. It was just that the process was so realistic.
- [BUG] Sometimes responses are generated that ignore the language setting.
- [BUG] Claude Code stuck with "Usage credits required for 1M context" even after /clear and available usage limit
- [BUG] Model selection not persisting - Max subscription triggers usage credits error for 1M context
- Subagent ignores explicit instruction to skip test execution
- [BUG] Claude Code v2.1.160 forces 1M context on Windows VS Code, blocks session continuation after error
- [BUG] Why I can not use Sonnet even I have enough quota?!
- Claude Code (Opus 4.7) silently narrows user-assigned task scope using self-generated safety heuristic, even when explicit in-session directive and persistent memory forbid it; laundered through external reviewer agent
- Claude repeatedly ignores tool rejections and burns user tokens
- App Build with Terrible Results
- Memory and instructions not effectively followed across sessions - repeated mistakes waste tokens and user time
- Claude Code agent wasted ~5 hours of user time across ~10 deployments — full incident log
- [BUG] own claude said to me when it was terrible and made me lost money, time and reach the limit improperly.
- [Bug] Repeated tool hallucinations causing workflow disruptions and token waste
- [Bug] Infinite thinking loop consuming all tokens without tool execution
- [BUG] Ignoring CLOUDE.MD instructions
- [BUG] Inconsistencies between Claude Code CLI and Claude Code in Desktop app: MCPs, Skills, async usage, and opusplan mode
- [BUG] Claude Code not respecting CLAUDE.md, unresolved and well-documented bug that has been reported for at least a month.
- Model inflates trivial tasks into complex ones to avoid execution; only acts under user escalation
- Claude claims to write memory/save plan but silently doesn't, then context resets
- [FEATURE] Raise default thinking budget / auto-escalate on diagnostic prompts
- [BUG] Claude Code generated automated claude-bridge subprocess that caused account suspension — no-code user, $367 lost
- CLAUDE.md rules not reliably enforced — model ignores its own checklist
- [BUG] my issue were not solved keep on hallucinating
- [Bug] Agent ignores user instructions and responds unpredictably
- Completion theater: Claude Code declares multi-session projects "complete" without valid verification
- [Bug] Claude ignores memory file instructions and hallucinates code behavior
- [BUG] Model retries identical failing Edit tool call multiple times without diagnosing error
- [BUG] Claude Code repeatedly uses Bash syntax (extglob) on Windows PowerShell and fails to adapt
- [BUG] No longer follows CLAUDE.MD instructions for reading procedures
- Opus 4.6 hallucinations & issues - Presents simulated data as real & ohters things.
- Add simple model configuration command and new model notifications
- context burning in Opus when switch to Sonnet is ignored
- [Bug] Unable to access Claude Sonnet model via /model command
- [Bug] Anthropic API Error: Internal server error with Claude 4.5 Sonnet
- [BUG] Changing model in a different session affects ALL sessions across different projects
- [BUG] Claude Code performed destructive mass file operations beyond requested scope
- Œ
- Missing Opus Model Option on windows Claude Code CLI
- Model Version Display in CLI Prompt
- [BUG] Stuck with Sonnet model as a Max user
- Responses drift into English mid-task despite `language: "japanese"` and CLAUDE.md language rules