# Buggy code
def file_md5(fname):
    """get the (md5 hexdigest, md5 digest) of a file"""
    from dvc.progress import progress
    from dvc.istextfile import istextfile

    if os.path.exists(fname):
        hash_md5 = hashlib.md5()
        binary = not istextfile(fname)
        size = os.path.getsize(fname)
        bar = False
        if size >= LARGE_FILE_SIZE:
            bar = True
            msg = "Computing md5 for a large file {}. This is only done once."
            logger.info(msg.format(os.path.relpath(fname)))
            name = os.path.relpath(fname)
            total = 0

        with open(fname, "rb") as fobj:
            while True:
                data = fobj.read(LOCAL_CHUNK_SIZE)
                if not data:
                    break

                if bar:
                    total += len(data)
                    progress.update_target(name, total, size)

                if binary:
                    chunk = data
                else:
                    chunk = dos2unix(data)

                hash_md5.update(chunk)

        if bar:
            progress.finish_target(name)

        return (hash_md5.hexdigest(), hash_md5.digest())
    else:
        return (None, None)


# Traceback (ValueError)
ERROR: failed to pull data from the cloud - path is on mount 'F:', start on mount 'C:'
Traceback (most recent call last):
File "c:\users\srg\appdata\local\continuum\anaconda3\envs\tf-keras\lib\site-packages\dvc\command\data_sync.py", line 46, in
do_run recursive=self.args.recursive,
File "c:\users\srg\appdata\local\continuum\anaconda3\envs\tf-keras\lib\site-packages\dvc\repo\pull.py", line 24, in pull
recursive=recursive,
File "c:\users\srg\appdata\local\continuum\anaconda3\envs\tf-keras\lib\site-packages\dvc\repo\fetch.py", line 27, in fetch
used, jobs, remote=remote, show_checksums=show_checksums
File "c:\users\srg\appdata\local\continuum\anaconda3\envs\tf-keras\lib\site-packages\dvc\data_cloud.py", line 144, in pull
show_checksums=show_checksums,
File "c:\users\srg\appdata\local\continuum\anaconda3\envs\tf-keras\lib\site-packages\dvc\remote\local\__init__.py", line 493, in pull
download=True,
File "c:\users\srg\appdata\local\continuum\anaconda3\envs\tf-keras\lib\site-packages\dvc\remote\local\__init__.py", line 459, in _process
download=download,
File "c:\users\srg\appdata\local\continuum\anaconda3\envs\tf-keras\lib\site-packages\dvc\remote\local\__init__.py", line 358, in status
local_exists = self.cache_exists(md5s)
File "c:\users\srg\appdata\local\continuum\anaconda3\envs\tf-keras\lib\site-packages\dvc\remote\local\__init__.py", line 232, in cache_exists
return list(filter(lambda md5: not self.changed_cache_file(md5), md5s))
File "c:\users\srg\appdata\local\continuum\anaconda3\envs\tf-keras\lib\site-packages\dvc\remote\local\__init__.py", line 232, in <lambda>
return list(filter(lambda md5: not self.changed_cache_file(md5), md5s))
File "c:\users\srg\appdata\local\continuum\anaconda3\envs\tf-keras\lib\site-packages\dvc\remote\base.py", line 518, in changed_cache_file
actual = self.get_checksum(cache_info)
File "c:\users\srg\appdata\local\continuum\anaconda3\envs\tf-keras\lib\site-packages\dvc\remote\base.py", line 275, in get_checksum
checksum = self.get_file_checksum(path_info)
File "c:\users\srg\appdata\local\continuum\anaconda3\envs\tf-keras\lib\site-packages\dvc\remote\local\__init__.py", line 208, in get_file_checksum
return file_md5(path_info.path)[0]
File "c:\users\srg\appdata\local\continuum\anaconda3\envs\tf-keras\lib\site-packages\dvc\utils\__init__.py", line 48, in file_md5                      logger.info(msg.format(os.path.relpath(fname)))
File "c:\users\srg\appdata\local\continuum\anaconda3\envs\tf-keras\lib\ntpath.py", line 584, in relpath
path_drive, start_drive))                                                                                                                        ValueError: path is on mount 'F:', start on mount 'C:'

# Fixed code
def file_md5(fname):
    """get the (md5 hexdigest, md5 digest) of a file"""
    from dvc.progress import progress
    from dvc.istextfile import istextfile

    if os.path.exists(fname):
        hash_md5 = hashlib.md5()
        binary = not istextfile(fname)
        size = os.path.getsize(fname)
        bar = False
        if size >= LARGE_FILE_SIZE:
            bar = True
            msg = "Computing md5 for a large file {}. This is only done once."
            logger.info(msg.format(relpath(fname)))
            name = relpath(fname)
            total = 0

        with open(fname, "rb") as fobj:
            while True:
                data = fobj.read(LOCAL_CHUNK_SIZE)
                if not data:
                    break

                if bar:
                    total += len(data)
                    progress.update_target(name, total, size)

                if binary:
                    chunk = data
                else:
                    chunk = dos2unix(data)

                hash_md5.update(chunk)

        if bar:
            progress.finish_target(name)

        return (hash_md5.hexdigest(), hash_md5.digest())
    else:
        return (None, None)