Cowork: newly created project directories fail VirtioFS mount (race condition)

Bug Description

Creating a new project in Claude Cowork and immediately starting a session causes a VirtioFS mount RPC error. This affects all new project directories, regardless of whether the name contains spaces.

The mount succeeds if you manually interact with the directory first (e.g., rename it in Finder, or ls it in Terminal), suggesting a race condition where the VM attempts to mount the directory before it's fully visible through the VirtioFS/shared filesystem layer.

Steps to Reproduce

1. Open Claude Desktop → Cowork
2. Create a new project (any name, e.g., thread_bank_renewal)
3. Immediately attempt to start a cowork session
4. Result: RPC mount error

Error

RPC error: failed to mount /mnt/.virtiofs-root/shared/Documents/Claude/Projects/thread_bank_renewal as thread_bank_renewal: source path is not accessible: /mnt/.virtiofs-root/shared/Documents/Claude/Projects/thread_bank_renewal: stat /mnt/.virtiofs-root/shared/Documents/Claude/Projects/thread_bank_renewal: operation not permitted

Key Observation

If you manually rename the project folder in Finder (or even just ls the path in Terminal) before starting the session, it works. This strongly suggests the directory exists on the host but hasn't propagated through VirtioFS to the VM yet when the mount is attempted.

Expected Behavior

The mount should wait for / verify directory accessibility before attempting to mount, or retry with a short backoff.

Workaround

After creating a new project, open Terminal and run:

ls ~/Documents/Claude/Projects/<project-name>

Then start the cowork session.

Environment

• macOS (Darwin 25.3.0, Apple Silicon)
• Claude Desktop (latest as of 2026-03-25)