Vmmem Memory Usage on Windows: Solutions and Prevention

When using Docker Desktop on Windows, you may notice a process called vmmem consuming significant amounts of RAM even after closing all Docker containers and images. This is a common issue affecting Windows Subsystem for Linux (WSL2) users, as vmmem is the virtual machine process that powers WSL2 and Docker Desktop.

Problem Overview

Vmmem is the virtual machine process responsible for running WSL2 distributions and Docker Desktop. While it should release memory when containers are stopped, several factors can prevent proper cleanup:

• Background WSL distributions remain running
• Docker services continue operating after container shutdown
• Memory caching mechanisms in WSL2
• Software bugs in specific Docker Desktop versions

Immediate Solutions to Stop Vmmem

1. Shutdown WSL Completely

The most effective command to release vmmem memory:

wsl --shutdown

This command terminates all WSL distributions and the underlying virtual machine, immediately freeing the memory used by vmmem.

2. Stop Specific WSL Distributions

If you want to target specific distributions rather than shutting down everything:

# List all running WSL distributions
wsl --list --verbose

# Stop a specific distribution
wsl --terminate Ubuntu-22.04
wsl --terminate docker-desktop

3. Force Stop WSL Service

When standard shutdown methods don't work:

# Run as Administrator
taskkill /F /IM wslservice.exe

Docker Desktop Configuration

Disable Automatic Startup

Prevent Docker from running automatically when you log in:

1. Open Docker Desktop
2. Go to Settings → General
3. Uncheck "Start Docker Desktop when you log in"

Disable Automatic Updates

Some users reported memory issues related to automatic updates:

1. Open Docker Desktop
2. Go to Settings → Software updates
3. Uncheck "Automatically check for updates"

Advanced Configuration

Limit WSL2 Memory Usage

Create or edit the WSL configuration file to limit memory consumption:

# Create or edit %UserProfile%\.wslconfig
[wsl2]
memory=6GB        # Limits WSL2 to 6GB of RAM
processors=4      # Limits to 4 CPU cores
swap=1GB          # Sets swap space size

After modifying the configuration, restart WSL:

# Run PowerShell as Administrator
Restart-Service LxssManager

Troubleshooting Persistent Issues

Clear WSL Memory Cache

If vmmem continues using memory after shutdown:

wsl -d docker-desktop /bin/sh -c "sync; sleep 5; echo 3 > /proc/sys/vm/drop_caches"

Disable Hyper-V Services

For extreme cases where vmmem won't release memory:

1. Open Services (services.msc)
2. Find "Hyper-V Host Compute Service"
3. Set startup type to "Disabled" and stop the service

WARNING

Disabling Hyper-V services may affect other virtualization features on your system.

Manual Process Termination

As a last resort:

1. Open Task Manager
2. Go to the Details tab
3. Locate and end processes starting with "vm"

Prevention and Best Practices

1. Regularly update Docker Desktop - Newer versions often fix memory management issues
2. Use the latest WSL2 kernel - Ensure you have the most recent WSL updates
3. Monitor running distributions - Periodically check wsl --list --verbose
4. Configure appropriate memory limits - Use .wslconfig to prevent excessive memory usage
5. Shutdown WSL when not in use - Develop the habit of running wsl --shutdown after Docker sessions

INFO

As of Docker Desktop 4.29, many memory management issues have been resolved. Consider updating if you're experiencing persistent vmmem memory problems.

Conclusion

Vmmem memory usage is a known challenge with WSL2 and Docker Desktop on Windows. The most effective solution is the wsl --shutdown command, which properly terminates the virtual machine and releases all allocated memory. For persistent issues, combine this with configuration adjustments in .wslconfig and Docker Desktop settings to maintain control over your system's memory resources.