Unable to create environments or install packages after upgrading to ArcGIS Pro 2.2

Description

In the Python backstage, creating a new environment or cloning the existing 'arcgispro-py3' folder seems to succeed, but activating the environment and restarting the application results in 'arcgispro-py3' being active.

Consulting the conda_log.txt file (located in %LocalAppData%/ESRI/conda/conda_log.txt) reports one of the following errors:

Error:
CondaError: Cannot link a source that does not exist.

Error:
The environment C:\Users\<username>\AppData\Local\ESRI\conda\envs\envname doesn't contain NumPy, which is required for ArcGIS Pro.

Cause

The contents of C:\Program Files\ArcGIS\Pro\bin\python\pkgs are disorganized. While upgrading from 2.1 to 2.2, the *.pyc files are deleted. This causes Conda to fail when building and installing packages.

The packages are built using 2.1, but the process of getting the machine from ArcGIS Pro 2.1 to 2.2 leaves the folders in a disorganized state.

Solution or Workaround

Remove certain contents from the folder, as specified below. Making these changes requires administrative privileges.

1. On the machine, browse to the C:/Program Files/ArcGIS/Pro/bin/Python/pkgs folder.

Warning:   
When performing to the next step, do not delete the pkgs/cache folder.

2. Remove all remaining folders in the pkgs folder, except the cache folder. They have names such as asn1crypto-0.24.0-py36_0, attrs-17.4.0-py36_0, or bleach-2.1.3-py36_0.