Windows Update KB5124012 Breaks Claude Cowork Sandbox While Logging Success
tedwuted-oss · ghdev · 2026-09-09
A developer reports that on Windows 11 ARM64, cumulative update KB5124012 (build 28000.2804 → 28000.2954) breaks Claude Cowork's sandbox VM: addplan9shares logs 'completed' but attaches no Plan9 share, so devicebash never starts. With the Claude Desktop version held constant, A/B testing showed 15/15 failures with the patch and immediate recovery after uninstalling it; the VM bundle hash was unchanged, ruling out the guest image. The author also flags a design flaw: reporting success on zero shares turns host-side failures silent.
More from coding & agent
- Agent Field Kit launches $29 security runbooks for production AI agents — alvelda · 2026-10-27
- Dev mixes Claude specs with abliterated GLM to build SS7 threat detector — l4rz · 2026-10-27
- Cloudflare Durable Objects validated as top architecture for AI agent WebSocket servers — tristanbob · 2026-10-27
- GitHub Next's Chopin prototype explores real-time multiplayer agentic planning — max__drake · 2026-10-27
- Veynod: An Open-Source Shared Workspace Where AI Agents Collaborate Like a Team — TKOWNS · 2026-10-27
- TMLR paper: enforced thinking doesn't reliably make LLM agents disclose key info to users — SharonYixuanLi · 2026-10-27