# Buggy code
def _check_dvc_filename(fname):
    if not Stage.is_valid_filename(fname):
        raise StageFileBadNameError(
            "bad stage filename '{}'. Stage files should be named"
            " 'Dvcfile' or have a '.dvc' suffix (e.g. '{}.dvc').".format(
                os.path.relpath(fname), os.path.basename(fname)
            )
        )


# 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 _check_dvc_filename(fname):
    if not Stage.is_valid_filename(fname):
        raise StageFileBadNameError(
            "bad stage filename '{}'. Stage files should be named"
            " 'Dvcfile' or have a '.dvc' suffix (e.g. '{}.dvc').".format(
                relpath(fname), os.path.basename(fname)
            )
        )