How to fix error during connect: This error may indicate that the docker daemon is not running in Docker

The most common fix is simply starting Docker Desktop:

1. Click the Windows Start menu
2. Search for "Docker Desktop"
3. Click to launch the application
4. Wait for the whale icon in the system tray to stop animating (becomes solid)

Alternatively, you can start Docker Desktop from PowerShell:

Start-Process "C:\Program Files\Docker\Docker\Docker Desktop.exe"

After Docker Desktop starts, verify the daemon is accessible:

docker version

You should see both Client and Server information. If you only see Client info, the daemon is still not running.

Also check:

docker info

This provides detailed information about the Docker environment.

If Docker Desktop appears running but commands still fail, restart the service:

Using Windows Services:
1. Press Win+R, type services.msc, press Enter
2. Find "Docker Desktop Service"
3. Right-click and select "Restart"

Using PowerShell (as Administrator):

Restart-Service -Name "com.docker.service"

If you're switching between Linux and Windows containers, the daemon may be in the wrong mode:

Using PowerShell:

& 'C:\Program Files\Docker\Docker\DockerCli.exe' -SwitchDaemon

Using Command Prompt:

"C:\Program Files\Docker\Docker\DockerCli.exe" -SwitchDaemon

You may need to run this command multiple times if it doesn't work on the first try.

Docker Desktop requires virtualization support. Verify it's enabled:

Check if Hyper-V is enabled:
1. Open "Turn Windows features on or off"
2. Ensure "Hyper-V" is checked (all sub-features)
3. Ensure "Windows Hypervisor Platform" is checked
4. Restart Windows if you made changes

Check Task Manager for virtualization:
1. Open Task Manager (Ctrl+Shift+Esc)
2. Go to Performance tab
3. Look for "Virtualization: Enabled" at the bottom

If virtualization is disabled, you'll need to enable it in your BIOS/UEFI settings.

If using WSL2 backend (default for Windows Home), ensure it's up to date:

wsl --update
wsl --shutdown

Then restart Docker Desktop.

Check your WSL distributions:

wsl -l -v

You should see "docker-desktop" and "docker-desktop-data" distributions.

If other solutions don't work, reset Docker Desktop:

1. Open Docker Desktop
2. Click the gear icon (Settings)
3. Go to "Troubleshoot" (or click the bug icon)
4. Click "Reset to factory defaults"

Warning: This removes all containers, images, and volumes. Back up important data first.

As a last resort, perform a clean reinstall:

1. Uninstall Docker Desktop from Windows Settings > Apps
2. Delete remaining Docker data:

Remove-Item -Recurse -Force "$env:APPDATA\Docker"
   Remove-Item -Recurse -Force "$env:LOCALAPPDATA\Docker"
   Remove-Item -Recurse -Force "$env:PROGRAMDATA\Docker"
   Remove-Item -Recurse -Force "$env:PROGRAMDATA\DockerDesktop"

3. Restart Windows
4. Download and install the latest Docker Desktop from docker.com
5. Follow the installation prompts