[BUG] [BUG] Cowork frontend kills every process immediately - conversation_uuid validation fails on all sessions (macOS 26, SDK 2.1.30-2.1.45)

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Cowork is completely non-functional. The backend VM works perfectly on every boot (network connects, SDK installs, API reachable, OAuth approves, process spawns), but the frontend terminates every spawned process within 5-60 seconds via SIGTERM. No response is ever displayed to the user.
The web log shows the same error on every session:
[REACT_QUERY_CLIENT] QueryClient error: Error: path.conversation_uuid: Input should be a valid UUID, invalid character: expected an optional prefix of urn:uuid: followed by [0-9a-fA-F-], found l at 1
The frontend is passing local session IDs (prefixed with "local_") where the API expects a proper UUID. The backend processes the prompt successfully, but the frontend cannot match the response back to a conversation, so it kills the process and nothing is ever rendered.
Additionally, the frontend does not recognise SDK message types coming back from the VM:
[LOCAL_SESSION] unknown sdk message type: queue-operation
[LOCAL_SESSION] unknown sdk message type: rate_limit_event
This has been occurring continuously since February 5th 2026 through to today (February 19th), across SDK versions 2.1.30 through 2.1.45, surviving multiple full cache wipes, VM bundle deletions, app reinstalls, and reboots.

What Should Happen?

Cowork should display Claude's response after the backend successfully processes the prompt.

Error Messages/Logs

VM swift log: Backend is perfect, frontend kills every process
Every single VM boot completes all steps successfully:
[VM] 2026-02-19 09:15:53 [info] VM startup step: vm_boot completed
[VM] 2026-02-19 09:16:02 [info] Guest connected
[VM] 2026-02-19 09:16:02 [info] Network status: CONNECTED
[VM] 2026-02-19 09:16:02 [info] API reachability: REACHABLE
[VM] 2026-02-19 09:16:03 [info] SDK installed successfully: version=2.1.45
But every spawned process gets killed almost immediately:
[VM] 2026-02-19 09:19:39 [info] Process spawned: id=ef8cb8a1-725e-4cad-beee-be39be755dcd
[VM] 2026-02-19 09:20:30 [info] Process ef8cb8a1-725e-4cad-beee-be39be755dcd killed with signal: SIGTERM

[VM] 2026-02-19 09:25:20 [info] Process spawned: id=83762110-30d5-45ef-8936-e7f3feabc3a8
[VM] 2026-02-19 09:26:08 [info] Process 83762110-30d5-45ef-8936-e7f3feabc3a8 killed with signal: SIGTERM
This pattern repeats 20+ times per session. On Feb 16th alone, approximately 40 processes were spawned and immediately killed.
Web log: UUID validation error on every attempt
2026-02-19 07:20:56 [error] [REACT_QUERY_CLIENT] QueryClient error: Error: path.conversation_uuid: Input should be a valid UUID
2026-02-19 07:26:30 [error] [REACT_QUERY_CLIENT] QueryClient error: Error: path.conversation_uuid: Input should be a valid UUID
2026-02-19 07:29:55 [error] [REACT_QUERY_CLIENT] QueryClient error: Error: path.conversation_uuid: Input should be a valid UUID
2026-02-19 07:31:40 [error] [REACT_QUERY_CLIENT] QueryClient error: Error: path.conversation_uuid: Input should be a valid UUID
(... continues for every single attempt)

Steps to Reproduce

Open Claude Desktop on macOS 26+ (Apple Silicon)
Switch to the Cowork tab
Select any local folder (tested with both Desktop and Documents folders)
Send any prompt (e.g. "hello")
Observe: the UI hangs or shows no response
Send a second prompt - the first response may then appear, but the second will not
Check ~/Library/Logs/Claude/claude.ai-web.log for the UUID validation error
Check ~/Library/Logs/Claude/cowork_vm_swift.log to confirm the process was spawned and then killed with SIGTERM

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Claude 1.1.3541 (1e65e4) 2026-02-18T19:23:37.000Z

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

claude.ai-web.log
cowork_vm_node.log
cowork_vm_swift.log

Additional errors

Recurring Uncaught Error: Minified React error #418 on nearly every app launch
Persistent Failed to query trusted certificates: -25300 warning on every VM boot
[LOCAL_SESSION] unknown sdk message type: queue-operation and rate_limit_event when responses come back

What I've tried (none resolved it)

Multiple full app restarts and reboots
Deleted ~/Library/Application Support/Claude/vm_bundles/ (VM re-downloaded)
Deleted ~/Library/Application Support/Claude/local-agent-mode-sessions/
Full cache wipe: rm -rf ~/Library/Application Support/Claude/ and ~/Library/Caches/Claude/
Full app uninstall and reinstall
Multiple reboots between each attempt
Tested with different folders (Desktop and Documents)
Renamed folders to remove special characters (spaces, dots)
The issue persists across all folders and all attempts