Creating conda environment from .yml file - Error Report - anaconda

Question

I am trying to create a conda environment from .yml file. I am using Miniconda3, python 3.7.3 on Windows. I receive the following error report. Any ideas what could cause such a problem?
PS. I apologise if the question is not appropriate.
Traceback (most recent call last):
File "C:\Users\mariyana\Miniconda3\lib\site-packages\conda\exceptions.py", line 1003, in __call__
return func(*args, **kwargs)
File "C:\Users\mariyana\Miniconda3\lib\site-packages\conda_env\cli\main.py", line 73, in do_call
exit_code = getattr(module, func_name)(args, parser)
File "C:\Users\mariyana\Miniconda3\lib\site-packages\conda_env\cli\main_update.py", line 69, in execute
directory=os.getcwd())
File "C:\Users\mariyana\Miniconda3\lib\site-packages\conda_env\specs\__init__.py", line 40, in detect
if spec.can_handle():
File "C:\Users\mariyana\Miniconda3\lib\site-packages\conda_env\specs\yaml_file.py", line 18, in can_handle
self._environment = env.from_file(self.filename)
File "C:\Users\mariyana\Miniconda3\lib\site-packages\conda_env\env.py", line 143, in from_file
return from_yaml(yamlstr, filename=filename)
File "C:\Users\mariyana\Miniconda3\lib\site-packages\conda_env\env.py", line 129, in from_yaml
data = validate_keys(data, kwargs)
File "C:\Users\mariyana\Miniconda3\lib\site-packages\conda_env\env.py", line 34, in validate_keys
for key in data.keys():
AttributeError: 'NoneType' object has no attribute 'keys'
`$ C:\Users\mariyana\Miniconda3\Scripts\conda-env-script.py update --file spikesorting.yml`
environment variables:
CIO_TEST=<not set>
CONDA_AUTO_UPDATE_CONDA=false
CONDA_DEFAULT_ENV=spikesorting
CONDA_EXE=C:\Users\mariyana\Miniconda3\condabin\..\Scripts\conda.exe
CONDA_EXES="C:\Users\mariyana\Miniconda3\condabin\..\Scripts\conda.exe"
CONDA_PREFIX=C:\Users\mariyana\Miniconda3\envs\spikesorting
CONDA_PREFIX_1=C:\Users\mariyana\Miniconda3
CONDA_PROMPT_MODIFIER=(spikesorting)
CONDA_PYTHON_EXE=C:\Users\mariyana\Miniconda3\python.exe
CONDA_ROOT=C:\Users\mariyana\Miniconda3
CONDA_SHLVL=2
HOMEPATH=\Users\mariyana
PATH=C:\Users\mariyana\Miniconda3;C:\Users\mariyana\Miniconda3\Library\ming
w-w64\bin;C:\Users\mariyana\Miniconda3\Library\usr\bin;C:\Users\mariya
na\Miniconda3\Library\bin;C:\Users\mariyana\Miniconda3\Scripts;C:\User
s\mariyana\Miniconda3\bin;C:\Users\mariyana\Miniconda3\envs\spikesorti
ng;C:\Users\mariyana\Miniconda3\envs\spikesorting\Library\mingw-w64\bi
n;C:\Users\mariyana\Miniconda3\envs\spikesorting\Library\usr\bin;C:\Us
ers\mariyana\Miniconda3\envs\spikesorting\Library\bin;C:\Users\mariyan
a\Miniconda3\envs\spikesorting\Scripts;C:\Users\mariyana\Miniconda3\en
vs\spikesorting\bin;C:\Users\mariyana\Miniconda3\condabin;C:\ProgramDa
ta\Oracle\Java\javapath;C:\Program Files\Haskell\bin;C:\Program
Files\Haskell Platform\7.10.2-a\lib\extralibs\bin;C:\Program
Files\Haskell Platform\7.10.2-a\bin;C:\Program Files
(x86)\Lenovo\FusionEngine;C:\Program Files (x86)\Intel\iCLS
Client;C:\Program Files\Intel\iCLS Client;C:\WINDOWS\system32;C:\WINDO
WS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPowerShell\v1.0
;C:\Program Files (x86)\ATI Technologies\ATI.ACE\Core-
Static;C:\Program Files\Intel\Intel(R) Management Engine
Components\DAL;C:\Program Files (x86)\Intel\Intel(R) Management Engine
Components\DAL;C:\Program Files\Intel\Intel(R) Management Engine
Components\IPT;C:\Program Files (x86)\Intel\Intel(R) Management Engine
Components\IPT;C:\Program Files\Intel\WiFi\bin;C:\Program Files\Common
Files\Intel\WirelessCommon;C:\Program Files (x86)\Common
Files\lenovo\easyplussdk\bin;C:\emacs-24.5\bin;C:\Program
Files\Haskell Platform\7.10.2-a\mingw\bin;C:\Program Files
(x86)\Windows Kits\8.1\Windows Performance Toolkit;C:\Program
Files\Microsoft SQL Server\130\Tools\Binn;C:\Program
Files\Git\cmd;C:\Program Files (x86)\Skype\Phone;C:\Program
Files\nodejs;C:\WINDOWS\System32\OpenSSH;C:\Program
Files\PuTTY;C:\Program Files (x86)\Heimdal\bin;C:\Program
Files\Heimdal\bin;C:\Program Files\Secure
Endpoints\NetIDMgr;C:\Program Files\MATLAB\R2018b\bin;C:\Users\mariyan
a\AppData\Local\Programs\Python\Python37-32\Scripts;C:\Users\mariyana\
AppData\Local\Programs\Python\Python37-32;C:\Users\mariyana\AppData\Lo
cal\Programs\Python\Python35\Scripts;C:\Users\mariyana\AppData\Local\P
rograms\Python\Python35;C:\Users\mariyana\AppData\Roaming\cabal\bin;C:
\Users\mariyana\AppData\Local\Microsoft\WindowsApps;C:\Users\mariyana\
AppData\Local\Google\Cloud SDK\google-cloud-
sdk\bin;C:\Users\mariyana\AppData\Roaming\npm;.
PSMODULEPATH=;C:\Users\mariyana\AppData\Local\Google\Cloud SDK\google-cloud-
sdk\platform\PowerShell
REQUESTS_CA_BUNDLE=<not set>
SSL_CERT_FILE=<not set>
active environment : spikesorting
active env location : C:\Users\mariyana\Miniconda3\envs\spikesorting
shell level : 2
user config file : C:\home\.condarc
populated config files :
conda version : 4.6.14
conda-build version : not installed
python version : 3.7.3.final.0
base environment : C:\Users\mariyana\Miniconda3 (writable)
channel URLs : https://repo.anaconda.com/pkgs/main/win-64
https://repo.anaconda.com/pkgs/main/noarch
https://repo.anaconda.com/pkgs/free/win-64
https://repo.anaconda.com/pkgs/free/noarch
https://repo.anaconda.com/pkgs/r/win-64
https://repo.anaconda.com/pkgs/r/noarch
https://repo.anaconda.com/pkgs/msys2/win-64
https://repo.anaconda.com/pkgs/msys2/noarch
package cache : C:\Users\mariyana\Miniconda3\pkgs
C:\home\.conda\pkgs
C:\Users\mariyana\AppData\Local\conda\conda\pkgs
envs directories : C:\Users\mariyana\Miniconda3\envs
C:\home\.conda\envs
C:\Users\mariyana\AppData\Local\conda\conda\envs
platform : win-64
user-agent : conda/4.6.14 requests/2.21.0 CPython/3.7.3 Windows/10 Windows/10.0.17134
administrator : False
netrc file : None
offline mode : False
An unexpected error has occurred. Conda has prepared the above report.
If submitted, this report will be used by core maintainers to improve
future releases of conda.
Would you like conda to send this report to the core maintainers?

Answer 1

This can happen when your environment yaml file is broken or empty. I ran into the same issue and noticed that while playing around with conda, the content of my environment.yml got deleted. Therefore, the for loop in env.py fails due to a None object.