How to fix unable to prepare context: unable to evaluate symlinks in Dockerfile path: lstat Dockerfile: no such file or directory in Docker

First, check that your Dockerfile exists and is named correctly:

# List files in current directory
ls -la

# Check for hidden extensions (common on Windows)
ls -la | grep -i docker

The file must be named exactly Dockerfile with:
- Capital 'D'
- Lowercase 'f'
- No file extension (.txt, .dockerfile, etc.)

If you see Dockerfile.txt or DockerFile, rename it:

# Remove .txt extension
mv Dockerfile.txt Dockerfile

# Fix capitalization
mv DockerFile Dockerfile

The docker build command expects a build context directory. Ensure you're running it from the directory containing your Dockerfile:

# Navigate to your project directory
cd /path/to/your/project

# Build with current directory as context
docker build -t myimage .

The dot (.) at the end is crucial—it tells Docker to use the current directory as the build context. Without it, you'll get a "requires exactly 1 argument" error.

If your Dockerfile is in a subdirectory:

# Build with subdirectory as context
docker build -t myimage ./subdirectory

If you have a .dockerignore file, it might be excluding your Dockerfile or required files:

# View .dockerignore contents
cat .dockerignore

Common mistake: copying patterns from .gitignore that exclude directories needed for the build.

Remove or comment out any lines that exclude your Dockerfile or required build files:

# Don't do this:
# Dockerfile
# **/Dockerfile

# Be specific about what to ignore
node_modules
*.log
.git

If you're using a non-standard Dockerfile name (e.g., Dockerfile.dev, Dockerfile.prod), you must specify it with the -f flag:

# Build with custom Dockerfile name
docker build -f Dockerfile.dev -t myimage .

# Or with full path
docker build -f /path/to/custom/Dockerfile -t myimage .

Note: The path specified with -f must still be within the build context directory.

For docker-compose, specify the dockerfile in your docker-compose.yml:

services:
  app:
    build:
      context: .
      dockerfile: Dockerfile.dev

In CI/CD environments, this error often occurs when the Dockerfile wasn't committed:

# Check git status
git status

# If Dockerfile is untracked, add it
git add Dockerfile
git commit -m "Add Dockerfile"
git push

Also verify the file exists in your remote repository:

# List files in remote
git ls-tree -r HEAD --name-only | grep Dockerfile

In CI/CD pipelines, ensure your checkout step includes all files and doesn't have path filters excluding the Dockerfile.