Expected behavior

COPY command to copy a file from local to image

Actual behavior

doing a simple COPY command in Dockerfile is throwing this error when the file is in a folder (not same level as Dockerfile file)

Information

• Full output of the diagnostics from "Diagnose & Feedback" in the menu

Docker for Mac: version: 17.06.0-ce-mac19 (4cdec4294a50b2233146b09469b49937dabdebdd)
macOS: version 10.12.6 (build: 16G29)
logs: /tmp/04FF32A9-CA64-40EB-B0DC-AD3E13A6C7D5/20170731-232145.tar.gz
[OK] db.git
[OK] vmnetd
[OK] dns
[OK] driver.amd64-linux
[OK] virtualization VT-X
[OK] app
[OK] moby
[OK] system
[OK] moby-syslog
[OK] db
[OK] env
[OK] virtualization kern.hv_support
[OK] slirp
[OK] osxfs
[OK] moby-console
[OK] logs
[OK] docker-cli
[OK] menubar
[OK] disk

• A reproducible case if this is a bug, Dockerfiles FTW
  See the following commands as a sample:

FROM python:latest
RUN apt-get update
RUN apt-get install nano
RUN mkdir /code
WORKDIR /code
COPY /helpdesk/requirements.txt /code/

• Page URL if this is a docs issue or the name of a man page

Steps to reproduce the behavior

1. docker build -t test .