[BUG] Critical: WSL2 delay regression now unbearable — Pro Max Plan user, unresolved since January 2026

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report
• [x] I am using the latest version of Claude Code

Follow-up to #22855 — situation has become critical

I filed #22855 on Feb 3, 2026. Multiple users confirmed the same issue. It was labeled high-priority but nothing happened. It is now almost 2 months later and the problem has gotten dramatically worse.

What's Wrong?

Every single prompt in Claude Code on WSL2 has a massive delay before any response begins. This affects:

• VS Code extension
• CLI in terminal
• Every model (Opus 4.6, Sonnet, etc.)
• Every prompt complexity (even "hello")

The delay is in the thinking/pre-response phase, not in token streaming. Once the response finally starts, streaming speed is normal.

Timeline of degradation:

| Version | Date | Severity |
|---|---|---|
| Stable 2.1.17 | Jan 2026 | ✅ Works perfectly |
| 2.1.29 | Jan 23, 2026 | ⚠️ 1-6 min delays |
| 2.1.71 | Mar 10, 2026 | 🔴 Worse |
| 2.1.87 | Mar 31, 2026 | 🔴🔴🔴 Unbearable — nearly unusable |

The delay has been consistently getting worse with every version for the last ~20 releases.

What Should Happen?

Response should begin within seconds, as it does on:

• Native Linux (same account, same model) → instant
• WSL2 with stable 2.1.17 → instant
• claude.ai web interface → instant

Steps to Reproduce

1. Windows 11 + WSL2 (Ubuntu 24.04)
2. Install Claude Code 2.1.87 (latest)
3. Open any project or no project
4. Send any prompt — even "hello"
5. Wait. And wait. And wait.

Impact

• I am a Pro Max Plan subscriber paying €200/month
• This has been broken for 2+ months with no fix, no acknowledgment, no workaround
• WSL2 is the primary dev environment for a huge portion of Windows developers
• Multiple users confirmed this in #22855 — zero response from Anthropic
• The tool is becoming unusable on WSL2, which means paying customers are getting nothing for their money

Environment

| Component | Version |
|---|---|
| Claude Code | 2.1.87 |
| VS Code | 1.113.0 (Electron 39.8.3, Chromium 142, Node 22.22.1) |
| OS Host | Windows 11 (Build 26200) |
| WSL2 Distro | Ubuntu 24.04.4 LTS |
| WSL2 Kernel | 6.6.87.2-microsoft-standard-WSL2 |
| Node.js | v24.14.0 |
| npm | 11.9.0 |
| pnpm | 10.33.0 |
| Docker | 29.3.1 |
| CPU | Intel Core i9-12900H (20 threads) |
| RAM | 20 GB allocated to WSL2 |
| Login | Claude Max Account (Pro Max Plan) |
| Model | Opus 4.6 (1M context) |

Is this a regression?

Yes. Stable 2.1.17 (January 2026) works perfectly on the exact same WSL2 setup. Every version since has been progressively slower.

Related Issues

• #22855 — my original report (Feb 3, 2026, still open, no fix)
• #16429, #17330, #22497 — flagged as possible duplicates, also unresolved
• #37371 — seccomp/sandbox issues on WSL2
• #35951 — Search/Explore tools interrupted on WSL

What I've tried

• Complete uninstall + fresh install (multiple times)
• Different Node.js versions
• Different terminals (VS Code integrated, Windows Terminal, native bash)
• Clearing all caches and config
• Different projects and empty directories
• Different models (Opus, Sonnet)
• Nothing helps. Only downgrading to stable 2.1.17 fixes it.

Request

This needs to be investigated and fixed urgently. 2+ months of a critical regression affecting all WSL2 users with zero response is not acceptable for a $200/month product. Please escalate this to the engineering team.

cc @anthropics/claude-code-team