Conda更新后无法激活环境，报不支持的格式字符错误

I'm running macOS 10.13.2, and recently updated conda, homebrew, and npm all around the same time. I also remember conda updating the futures package (version 3.2.0 py27h1b80678_0), which I've seen mentioned in similar bug reports before.

Now when I try to run source activate py36 (or any conda environment activation command), I get this error:

Traceback (most recent call last):
File "/Users/gyaresu/miniconda2/lib/python2.7/site-packages/conda/gateways/logging.py", line 64, in emit
msg = self.format(record)
File "/Users/gyaresu/miniconda2/lib/python2.7/logging/__init__.py", line 734, in format
return fmt.format(record)
File "/Users/gyaresu/miniconda2/lib/python2.7/logging/__init__.py", line 465, in format
record.message = record.getMessage()
File "/Users/gyaresu/miniconda2/lib/python2.7/logging/__init__.py", line 329, in getMessage
msg = msg % self.args
File "/Users/gyaresu/miniconda2/lib/python2.7/site-packages/conda/__init__.py", line 43, in __repr__
return '%s: %s' % (self.__class__.__name__, text_type(self))
File "/Users/gyaresu/miniconda2/lib/python2.7/site-packages/conda/__init__.py", line 47, in __str__
return text_type(self.message % self._kwargs)
ValueError: unsupported format character '{' (0x7b) at index 445
Logged from file exceptions.py, line 724

Here's my environment information to help diagnose the issue:

Conda Info #

λ conda info
active environment : None
shell level : 0
user config file : /Users/gyaresu/.condarc
populated config files : /Users/gyaresu/.condarc
conda version : 4.4.7
conda-build version : not installed
python version : 2.7.14.final.0
base environment : /Users/gyaresu/miniconda2 (writable)
channel URLs : https://repo.continuum.io/pkgs/main/osx-64
https://repo.continuum.io/pkgs/main/noarch
https://repo.continuum.io/pkgs/free/osx-64
https://repo.continuum.io/pkgs/free/noarch
https://repo.continuum.io/pkgs/r/osx-64
https://repo.continuum.io/pkgs/r/noarch
https://repo.continuum.io/pkgs/pro/osx-64
https://repo.continuum.io/pkgs/pro/noarch
package cache : /Users/gyaresu/miniconda2/pkgs
/Users/gyaresu/.conda/pkgs
envs directories : /Users/gyaresu/miniconda2/envs
/Users/gyaresu/.conda/envs
platform : osx-64
user-agent : conda/4.4.7 requests/2.18.4 CPython/2.7.14 Darwin/17.3.0 OSX/10.13.2
UID:GID : 502:20
netrc file : /Users/gyaresu/.netrc
offline mode : False

System Python Info #

λ which python
/usr/local/opt/python/libexec/bin/python
λ python -V
Python 2.7.14

Homebrew Configuration #

λ brew config
HOMEBREW_VERSION: 1.4.3
ORIGIN: https://github.com/Homebrew/brew
HEAD: 987805d3dcd4c8dbc70127399d4ea7aee8e98c21
Last commit: 2 days ago
Core tap ORIGIN: https://github.com/Homebrew/homebrew-core
Core tap HEAD: eae0bcacf6aa1592ee0fdc2d424a1c63a0a2d17a
Core tap last commit: 8 hours ago
HOMEBREW_PREFIX: /usr/local
CPU: octa-core 64-bit ivybridge
Homebrew Ruby: 2.3.3 => /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/bin/ruby
Clang: 9.0 build 900
Git: 2.15.1 => /usr/local/bin/git
Curl: 7.54.0 => /usr/bin/curl
Perl: /usr/local/bin/perl => /usr/local/Cellar/perl/5.26.1/bin/perl
Python: /usr/local/opt/python/libexec/bin/python => /usr/local/Cellar/python/2.7.14_2/Frameworks/Python.framework/Versions/2.7/bin/python2.7
Ruby: /usr/local/bin/ruby => /usr/local/Cellar/ruby/2.5.0/bin/ruby
Java: 1.8.0_51, 1.6.0_65-b14-468
macOS: 10.13.2-x86_64
Xcode: N/A
CLT: 9.2.0.0.1.1510905681
X11: 2.7.11 => /opt/X11

I'm stuck and can't activate any of my conda environments. Any help figuring out what's going on and how to fix this would be greatly appreciated!

内容的提问来源于stack exchange，提问作者Gareth