RPC error -1: virtiofs mount failure after ~1 hour of use on Windows
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?
For the GitHub issue description, copy and paste exactly what you shared with me earlier:
Problem:
I'm experiencing a recurring crash with Claude Cowork on Windows. The error message is: RPC error -1: failed to ensure virtiofs mount: Plan9 mount failed: bad address
Details:
The error occurs after approximately 1 hour of use — Cowork launches and works fine, then crashes after extended use
Restarting Cowork temporarily fixes it, but the error returns after another ~45 minutes to an hour
System: Windows 11, Lenovo Legion PC
Windows features enabled: Virtual Machine Platform, Windows Hypervisor Platform, Windows Subsystem for Linux (WSL2), Windows Projected File System
I enabled WSL and Windows Projected File System based on troubleshooting suggestions — it may have extended the time before crashing but did not resolve the issue
This appears to be a memory or resource leak in the virtiofs/Plan9 layer rather than a configuration issue, since it works fine on startup but degrades over time.
That gives the developers all the technical details they need to investigate your issue.
What Should Happen?
Expected behavior:
Claude Cowork should run continuously without crashing. The virtiofs mount should remain stable during extended use sessions (multiple hours) without requiring restarts.
Current behavior:
RPC error -1 occurs after ~1 hour, requiring restart to temporarily resolve.
This tells the developers exactly what the ideal outcome should be versus what's actually happening with your setup.
Error Messages/Logs
RPC error -1: failed to ensure virtiofs mount: Plan9 mount failed: bad addressSteps to Reproduce
Install and launch Claude Cowork on Windows 11 (Lenovo Legion PC)
Begin working normally — Cowork functions without issue on startup
Continue using Cowork for approximately 45 minutes to 1 hour
After extended use, Cowork crashes with the following error:
RPC error -1: failed to ensure virtiofs mount: Plan9 mount failed: bad address
Restarting Cowork resolves the error temporarily
After another ~45 minutes to 1 hour of use, the error recurs
System configuration:
OS: Windows 11
Hardware: Lenovo Legion
Windows features enabled: Virtual Machine Platform, Windows Hypervisor Platform, Windows Subsystem for Linux (WSL2), Windows Projected File System
Note: WSL2 and Windows Projected File System were enabled during troubleshooting and may have slightly extended the time before crashing, but did not resolve the underlying issue.
Claude Model
Sonnet (default)
Is this a regression?
I don't know
Last Working Version
Unknown — this has been occurring since I first installed Cowork and I have not had a version that worked reliably beyond ~1 hour of use.
Claude Code Version
N/A — this issue is with Claude Cowork desktop app, not Claude Code. Version unknown.
Platform
Anthropic API
Operating System
Windows
Terminal/Shell
Windows Terminal
Additional Information
Restarting Cowork temporarily resolves the error, suggesting a memory or resource leak in the virtiofs/Plan9 layer rather than a configuration issue. The crash consistently occurs after ~45 minutes to 1 hour of use, not on startup.
Troubleshooting already attempted:
Enabled Windows Subsystem for Linux (WSL2)
Enabled Windows Projected File System
Enabled Virtual Machine Platform and Windows Hypervisor Platform (were already enabled)
Restarting Windows temporarily extended time before crash but did not resolve it
The /bug and /doctor commands in Cowork are not functional — per Anthropic's Fin AI support agent, this is a known skills functionality issue currently shown on the status page, which is why this bug is being reported via GitHub instead.
<img width="348" height="556" alt="Image" src="https://github.com/user-attachments/assets/f5cc2743-5063-4e97-8a23-15c97361b681" />
8 Comments
Found 3 possible duplicate issues:
This issue will be automatically closed as a duplicate in 3 days.
🤖 Generated with Claude Code
attaching system info
OS Name Microsoft Windows 11 Home
Version 10.0.26200 Build 26200
Other OS Description Not Available
OS Manufacturer Microsoft Corporation
System Name MOMMYSPOWERTRIP
System Manufacturer LENOVO
System Model 90V6000MUS
System Type x64-based PC
System SKU LENOVO_MT_90V6_BU_Lenovo_FM_Legion T7 34IRZ8
Processor Intel(R) Core(TM) i9-14900KF, 3200 Mhz, 24 Core(s), 32 Logical Processor(s)
BIOS Version/Date LENOVO O5UKT3FA, 8/9/2024
SMBIOS Version 3.6
Embedded Controller Version 1.16
BIOS Mode UEFI
BaseBoard Manufacturer LENOVO
BaseBoard Product 376A
BaseBoard Version SDK0T76461 WIN 3422119405729
Platform Role Desktop
Secure Boot State On
PCR7 Configuration Elevation Required to View
Windows Directory C:\WINDOWS
System Directory C:\WINDOWS\system32
Boot Device \Device\HarddiskVolume1
Locale United States
Hardware Abstraction Layer Version = "10.0.26100.1"
User Name MommysPowerTrip\juhll
Time Zone Pacific Standard Time
Installed Physical Memory (RAM) 32.0 GB
Total Physical Memory 31.7 GB
Available Physical Memory 17.5 GB
Total Virtual Memory 128 GB
Available Virtual Memory 109 GB
Page File Space 96.0 GB
Page File C:\pagefile.sys
Kernel DMA Protection On
Virtualization-based security Running
Virtualization-based security Required Security Properties
Virtualization-based security Available Security Properties Base Virtualization Support, Secure Boot, DMA Protection, UEFI Code Readonly, SMM Security Mitigations 1.0, Mode Based Execution Control, APIC Virtualization
Virtualization-based security Services Configured Hypervisor enforced Code Integrity
Virtualization-based security Services Running Hypervisor enforced Code Integrity
App Control for Business policy Enforced
App Control for Business user mode policy Off
Automatic Device Encryption Support Elevation Required to View
A hypervisor has been detected. Features required for Hyper-V will not be displayed.
Closing as duplicate of #26554, which is tracking the core RPC error -1: failed to ensure virtiofs mount: Plan9 mount failed: bad address issue.
The time-based degradation pattern reported here (works on startup, fails after ~1 hour) is a useful data point, it suggests a possible resource or handle leak in the virtiofs/Plan9 layer.
OS: Windows 11 Home
Cowork version: Latest (as of March 2026)
Issue: RPC error -1: failed to ensure virtiofs mount: Plan9 mount failed: bad address
Steps taken:
Enabled VirtualMachinePlatform and HypervisorPlatform via PowerShell (admin)
Restarted PC
Cowork worked for ~10 minutes after setup, then crashed with the above error
Behaviour: Error recurs every ~10 minutes, requiring a full Cowork restart each time. This is not a configuration issue as the required Windows features are enabled.
Expected: Cowork should remain stable during extended use sessions.
Why has this been closed? I did not find a solution.
same error here!
Community workaround: automated fix toolkit for Windows
I kept hitting this exact error and got tired of rebooting, so I built a set of PowerShell scripts that fix it without a reboot and prevent it from coming back.
What it does:
What it doesn't touch: config files, MCP servers, conversations — only the VM cache.
Repo: https://github.com/JesperLive/ClaudeFix
Tested on Windows 10 and 11. Feedback welcome — especially if you hit edge cases it doesn't handle.
This issue has been automatically locked since it was closed and has not had any activity for 7 days. If you're experiencing a similar issue, please file a new issue and reference this one if it's relevant.