I am attempting to build a container on a Windows machine, but I keep getting the error "unable to prepare context: unable to evaluate symlinks in Dockerfile path." It seems like Docker is struggling with the file path or the way Windows handles symbolic links within the build context. Is this an issue with how I’m pointing to the Dockerfile in my CLI command, or does it have something to do with the permissions of the directory I am currently working in?
3 answers
This error usually occurs in a Windows environment when the path provided to the -f flag in your docker build command is incorrect or improperly formatted. In software development, Docker expects the build context (the period . at the end of the command) to be the root. If your Dockerfile is in the current directory, you don't need to specify a full path. Often, this error is triggered because of a typo in the filename—like dockerfile instead of Dockerfile—or because you are attempting to reference a Dockerfile that is outside the build context directory. Ensure you are running the command from the root of your project and that the Dockerfile is physically present in the location you've specified.
I’ve noticed this happens more often when using Git Bash on Windows versus PowerShell. Could the shell's translation of POSIX paths be causing the "GetFileAttributesEx" failure during the symlink evaluation?
Check if your Dockerfile has a hidden .txt extension. Windows sometimes hides extensions, making the file Dockerfile.txt, which triggers this exact error when you call Dockerfile.
I agree with Brett. This is a classic "gotcha" for developers new to the Windows environment. I once spent two hours debugging a CI pipeline only to find that the text editor had appended an extension. Renaming the file via the command line ensures there are no hidden suffixes interfering with the Docker daemon's ability to locate the build instructions.
Joshua, you are absolutely on the right track. Git Bash often tries to "help" by converting paths, which can lead to the GetFileAttributesEx error because Docker for Windows expects a format it can natively understand. To fix this, try wrapping your path in double quotes or, even better, switch to PowerShell for the build command. PowerShell handles the file system calls much more consistently with the Docker Desktop backend, which usually resolves the symlink evaluation issue immediately without changing your actual project structure.