Conda takes 20+ minutes to solve environment when package is already installed : <p>NOTE:
I'm duplicating this post because the question has been up on the conda github page for ~6-days with no response.  The original link is here:
<a href="https://github.com/conda/conda/issues/7938" rel="noreferrer">https://github.com/conda/conda/issues/7938</a></p>

<h2>Current Behavior</h2>

<p>When I type try to run <code>conda update -n base conda</code>, conda hung for around 20-minutes on 'Solving environment' and then returned a package plan that did not include an updated version of conda.  The package plan that was returned is provided below.  </p>

<p><strong>The package plan that was returned is as follows:</strong></p>

<pre><code>environment location: C:\Users\jmatt\Anaconda3
added / updated specs:
    - conda


The following packages will be downloaded:

package                    |            build
---------------------------|-----------------
libarchive-3.3.2           |       h1d0d21d_1         4.0 MB
lz4-c-1.8.2                |           vc14_0         254 KB  conda-forge
libcurl-7.61.1             |       h7602738_0         249 KB
------------------------------------------------------------
                                       Total:         4.5 MB

The following packages will be UPDATED:

jpeg:       9b-hb83a4c4_2         --&gt; 9b-vc14_2             conda-forge [vc14]
libcurl:    7.61.1-h2a8f88b_0     --&gt; 7.61.1-h7602738_0
libsodium:  1.0.16-h9d3ae62_0     --&gt; 1.0.16-vc14_0         conda-forge [vc14]
libxslt:    1.1.32-hf6f1972_0     --&gt; 1.1.32-vc14_0         conda-forge [vc14]
lz4-c:      1.8.1.2-h2fa13f4_0    --&gt; 1.8.2-vc14_0          conda-forge [vc14]
tk:         8.6.8-hfa6e2cd_0      --&gt; 8.6.8-vc14_0          conda-forge [vc14]
zeromq:     4.2.5-he025d50_1      --&gt; 4.2.5-vc14_2          conda-forge [vc14]

The following packages will be DOWNGRADED:

astropy:    3.0.5-py36he774522_0  --&gt; 3.0.4-py36hfa6e2cd_0
bzip2:      1.0.6-hfa6e2cd_5      --&gt; 1.0.6-vc14_1          conda-forge [vc14]
curl:       7.61.1-h2a8f88b_0     --&gt; 7.60.0-vc14_0         conda-forge [vc14]
cython:     0.29-py36ha925a31_0   --&gt; 0.28.5-py36h6538335_0
freetype:   2.9.1-ha9979f8_1      --&gt; 2.8.1-vc14_0          conda-forge [vc14]
gevent:     1.3.7-py36he774522_1  --&gt; 1.3.6-py36hfa6e2cd_0
hdf5:       1.10.2-hac2f561_1     --&gt; 1.10.2-vc14_0         conda-forge [vc14]
icu:        58.2-ha66f8fd_1       --&gt; 58.2-vc14_0           conda-forge [vc14]
krb5:       1.16.1-h038dc86_6     --&gt; 1.14.6-vc14_0         conda-forge [vc14]
libarchive: 3.3.3-h798a506_0      --&gt; 3.3.2-h1d0d21d_1
libiconv:   1.15-h1df5818_7       --&gt; 1.14-vc14_4           conda-forge [vc14]
libpng:     1.6.35-h2a8f88b_0     --&gt; 1.6.34-vc14_0         conda-forge [vc14]
libtiff:    4.0.9-h36446d0_2      --&gt; 4.0.9-vc14_0          conda-forge [vc14]
libxml2:    2.9.8-hadb2253_1      --&gt; 2.9.5-vc14_1          conda-forge [vc14]
llvmlite:   0.25.0-py36_0         --&gt; 0.24.0-py36h6538335_0
lxml:       4.2.5-py36hef2cd61_0  --&gt; 4.1.1-py36he0adb16_0
lzo:        2.10-h6df0209_2       --&gt; 2.10-vc14_0           conda-forge [vc14]
matplotlib: 3.0.0-py36hd159220_0  --&gt; 2.2.2-py36h153e9ff_0
mistune:    0.8.4-py36he774522_0  --&gt; 0.8.3-py36hfa6e2cd_1
numba:      0.40.0-py36hf9181ef_0 --&gt; 0.39.0-py36h830ac7b_0
pillow:     5.3.0-py36hdc69c19_0  --&gt; 5.1.0-py36h0738816_0
pyqt:       5.9.2-py36h6538335_2  --&gt; 5.6.0-py36_2
pywavelets: 1.0.1-py36h8c2d366_0  --&gt; 1.0.0-py36h452e1ab_0
qt:         5.9.6-vc14h1e9a669_2  --&gt; 5.6.2-vc14_1          conda-forge [vc14]
snappy:     1.1.7-h777316e_3      --&gt; 1.1.7-vc14_1          conda-forge [vc14]
sqlalchemy: 1.2.12-py36he774522_0 --&gt; 1.2.11-py36hfa6e2cd_0
sqlite:     3.25.2-hfa6e2cd_0     --&gt; 3.22.0-vc14_0         conda-forge [vc14]
twisted:    18.9.0-py36he774522_0 --&gt; 18.7.0-py36hfa6e2cd_1
vc:         14.1-h0510ff6_4       --&gt; 14-h0510ff6_3
yaml:       0.1.7-hc54c509_2      --&gt; 0.1.7-vc14_0          conda-forge [vc14]
zlib:       1.2.11-h8395fce_2     --&gt; 1.2.11-vc14_0         conda-forge [vc14]

Proceed ([y]/n)? n
</code></pre>

<p></p>

<p><br/></p>

<p>NOTE: the conda version I have installed is 4.5.11 - I'm not sure if this is the most recent version and haven't been able to find a command or resource (other than <code>conda update conda</code>) to check what the most recent version is.  I also had a similar problem when trying to <code>conda install websocket-client</code> when websocket client was already installed - I wonder if the current version of conda has trouble when the most recent version of a package is already installed.</p>

<p>NOTE 2: <code>conda update --all</code> solved the environment in a reasonable amount of time (~1 min - I didn't time it precisely).</p>

<h3>Steps to Reproduce</h3>

<p><code>
conda update -n base conda
</code></p>

<p>As I mentioned above, <code>conda install websocket-client</code> also hung at 'Solving environment' - I already had websocket-client version 0.53.0 installed when I tried to run the install command</p>

<h2>Expected Behavior</h2>

<p>Conda should either:
1. If the most recent version is installed, conda should promptly inform the user that an update isn't needed.
1. If a newer version is available, I'd expect Conda to solve the environment in a shorter period of time. I think that less than 1-2 minutes would be reasonable - 20+ minutes is too long</p>

<h2>Environment Information</h2>

<p>The output of: <code>conda info</code><p>
</p>

<p><code>active environment : base
    active env location : C:\Users\jmatt\Anaconda3
            shell level : 1
       user config file : C:\Users\jmatt\.condarc
 populated config files : C:\Users\jmatt\.condarc
          conda version : 4.5.11
    conda-build version : 3.16.1
         python version : 3.6.6.final.0
       base environment : C:\Users\jmatt\Anaconda3  (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/pro/win-64
                          https://repo.anaconda.com/pkgs/pro/noarch
                          https://repo.anaconda.com/pkgs/msys2/win-64
                          https://repo.anaconda.com/pkgs/msys2/noarch
                          https://conda.anaconda.org/conda-forge/win-64
                          https://conda.anaconda.org/conda-forge/noarch
          package cache : C:\Users\jmatt\Anaconda3\pkgs
                          C:\Users\jmatt\AppData\Local\conda\conda\pkgs
       envs directories : C:\Users\jmatt\Anaconda3\envs
                          C:\Users\jmatt\AppData\Local\conda\conda\envs
                          C:\Users\jmatt\.conda\envs
               platform : win-64
             user-agent : conda/4.5.11 requests/2.19.1 CPython/3.6.6 Windows/10 Windows/10.0.17134
          administrator : False
             netrc file : None
           offline mode : False</code>
</p></p>

<p>The output of: <code>conda config --show-sources</code><p>
</p>

<p><code>ssl_verify: True
channels:
  - defaults
  - conda-forge</code>
</p></p>

<p>The output of: <code>conda list --show-channel-urls</code><p>
</p>

<p><code>(base) C:\Users\jmatt&gt;conda list --show-channel-urls
packages in environment at C:\Users\jmatt\Anaconda3:
 Name                    Version                   Build  Channel
_ipyw_jlab_nb_ext_conf    0.1.0                    py36_0    defaults
alabaster                 0.7.12                   py36_0    defaults
anaconda                  custom           py36h363777c_0    defaults
anaconda-client           1.7.2                    py36_0    defaults
anaconda-navigator        1.9.2                    py36_0    defaults
anaconda-project          0.8.2                    py36_0    defaults
appdirs                   1.4.3            py36h28b3542_0    defaults
asn1crypto                0.24.0                   py36_0    defaults
astroid                   2.0.4                    py36_0    defaults
astropy                   3.0.5            py36he774522_0    defaults
atomicwrites              1.2.1                    py36_0    defaults
attrs                     18.2.0           py36h28b3542_0    defaults
automat                   0.7.0                    py36_0    defaults
babel                     2.6.0                    py36_0    defaults
backcall                  0.1.0                    py36_0    defaults
backports                 1.0                      py36_1    defaults
backports.os              0.1.1                    py36_0    defaults
backports.shutil_get_terminal_size 1.0.0                    py36_2    defaults
beautifulsoup4            4.6.3                    py36_0    defaults
bitarray                  0.8.3            py36hfa6e2cd_0    defaults
bkcharts                  0.2              py36h7e685f7_0    defaults
blas                      1.0                         mkl    defaults
blaze                     0.11.3                   py36_0    defaults
bleach                    3.0.2                    py36_0    defaults
blosc                     1.14.4               he51fdeb_0    defaults
bokeh                     0.13.0                   py36_0    defaults
boto                      2.49.0                   py36_0    defaults
bottleneck                1.2.1            py36h452e1ab_1    defaults
bzip2                     1.0.6                hfa6e2cd_5    defaults
ca-certificates           2018.03.07                    0    defaults
certifi                   2018.10.15               py36_0    defaults
cffi                      1.11.5           py36h74b6da3_1    defaults
chardet                   3.0.4                    py36_1    defaults
click                     7.0                      py36_0    defaults
cloudpickle               0.6.1                    py36_0    defaults
clyent                    1.2.2                    py36_1    defaults
colorama                  0.4.0                    py36_0    defaults
comtypes                  1.1.7                    py36_0    defaults
conda                     4.5.11                   py36_0    defaults
conda-build               3.16.1                   py36_0    defaults
conda-env                 2.6.0                         1    defaults
conda-verify              3.1.1                    py36_0    defaults
console_shortcut          0.1.1                         3    defaults
constantly                15.1.0           py36h28b3542_0    defaults
contextlib2               0.5.5            py36he5d52c0_0    defaults
cryptography              2.3.1            py36h74b6da3_0    defaults
curl                      7.61.1               h2a8f88b_0    defaults
cycler                    0.10.0           py36h009560c_0    defaults
cython                    0.29             py36ha925a31_0    defaults
cytoolz                   0.9.0.1          py36hfa6e2cd_1    defaults
dask                      0.19.4                   py36_0    defaults
dask-core                 0.19.4                   py36_0    defaults
datashape                 0.5.4                    py36_1    defaults
decorator                 4.3.0                    py36_0    defaults
defusedxml                0.5.0                    py36_1    defaults
distributed               1.23.3                   py36_0    defaults
docutils                  0.14             py36h6012d8f_0    defaults
entrypoints               0.2.3                    py36_2    defaults
et_xmlfile                1.0.1            py36h3d2d736_0    defaults
fastcache                 1.0.2            py36hfa6e2cd_2    defaults
filelock                  3.0.9                    py36_0    defaults
flask                     1.0.2                    py36_1    defaults
flask-cors                3.0.6                    py36_0    defaults
freetype                  2.9.1                ha9979f8_1    defaults
future                    0.16.0                   py36_2    defaults
geographiclib             1.49                       py_0    conda-forge
geopy                     1.17.0                     py_0    conda-forge
get_terminal_size         1.0.0                h38e98db_0    defaults
gevent                    1.3.7            py36he774522_1    defaults
glob2                     0.6                      py36_1    defaults
greenlet                  0.4.15           py36hfa6e2cd_0    defaults
h5py                      2.8.0            py36h3bdd7fb_2    defaults
hdf5                      1.10.2               hac2f561_1    defaults
heapdict                  1.0.0                    py36_2    defaults
html5lib                  1.0.1                    py36_0    defaults
hyperlink                 18.0.0                   py36_0    defaults
icc_rt                    2017.0.4             h97af966_0    defaults
icu                       58.2                 ha66f8fd_1    defaults
idna                      2.7                      py36_0    defaults
imageio                   2.4.1                    py36_0    defaults
imagesize                 1.1.0                    py36_0    defaults
importlib_metadata        0.6                      py36_0    defaults
incremental               17.5.0                   py36_0    defaults
intel-openmp              2019.0                      118    defaults
ipykernel                 5.1.0            py36h39e3cac_0    defaults
ipython                   7.0.1            py36h39e3cac_0    defaults
ipython_genutils          0.2.0            py36h3c5d0ee_0    defaults
ipywidgets                7.4.2                    py36_0    defaults
isort                     4.3.4                    py36_0    defaults
itsdangerous              1.0.0                    py36_0    defaults
jdcal                     1.4                      py36_0    defaults
jedi                      0.13.1                   py36_0    defaults
jinja2                    2.10                     py36_0    defaults
jpeg                      9b                   hb83a4c4_2    defaults
jsonschema                2.6.0            py36h7636477_0    defaults
jupyter                   1.0.0                    py36_7    defaults
jupyter_client            5.2.3                    py36_0    defaults
jupyter_console           6.0.0                    py36_0    defaults
jupyter_core              4.4.0                    py36_0    defaults
jupyterlab                0.35.2                   py36_0    defaults
jupyterlab_launcher       0.13.1                   py36_0    defaults
jupyterlab_server         0.2.0                    py36_0    defaults
keyring                   15.1.0                   py36_0    defaults
kiwisolver                1.0.1            py36h6538335_0    defaults
krb5                      1.16.1               h038dc86_6    defaults
lazy-object-proxy         1.3.1            py36hfa6e2cd_2    defaults
libarchive                3.3.3                h798a506_0    defaults
libcurl                   7.61.1               h2a8f88b_0    defaults
libiconv                  1.15                 h1df5818_7    defaults
libpng                    1.6.35               h2a8f88b_0    defaults
libsodium                 1.0.16               h9d3ae62_0    defaults
libssh2                   1.8.0                hd619d38_4    defaults
libtiff                   4.0.9                h36446d0_2    defaults
libxml2                   2.9.8                hadb2253_1    defaults
libxslt                   1.1.32               hf6f1972_0    defaults
llvmlite                  0.25.0                   py36_0    defaults
locket                    0.2.0            py36hfed976d_1    defaults
lxml                      4.2.5            py36hef2cd61_0    defaults
lz4-c                     1.8.1.2              h2fa13f4_0    defaults
lzo                       2.10                 h6df0209_2    defaults
m2w64-gcc-libgfortran     5.3.0                         6    defaults
m2w64-gcc-libs            5.3.0                         7    defaults
m2w64-gcc-libs-core       5.3.0                         7    defaults
m2w64-gmp                 6.1.0                         2    defaults
m2w64-libwinpthread-git   5.0.0.4634.697f757               2    defaults
markupsafe                1.0              py36hfa6e2cd_1    defaults
matplotlib                3.0.0            py36hd159220_0    defaults
mccabe                    0.6.1                    py36_1    defaults
menuinst                  1.4.14           py36hfa6e2cd_0    defaults
mistune                   0.8.4            py36he774522_0    defaults
mkl                       2019.0                      118    defaults
mkl-service               1.1.2            py36hb217b18_5    defaults
mkl_fft                   1.0.6            py36hdbbee80_0    defaults
mkl_random                1.0.1            py36h77b88f5_1    defaults
more-itertools            4.3.0                    py36_0    defaults
mpmath                    1.0.0                    py36_2    defaults
msgpack-python            0.5.6            py36he980bc4_1    defaults
msys2-conda-epoch         20160418                      1    defaults
multipledispatch          0.6.0                    py36_0    defaults
navigator-updater         0.2.1                    py36_0    defaults
nbconvert                 5.3.1                    py36_0    defaults
nbformat                  4.4.0            py36h3a5bc1b_0    defaults
networkx                  2.2                      py36_1    defaults
nltk                      3.3.0                    py36_0    defaults
nose                      1.3.7                    py36_2    defaults
notebook                  5.7.0                    py36_0    defaults
numba                     0.40.0           py36hf9181ef_0    defaults
numexpr                   2.6.8            py36h9ef55f4_0    defaults
numpy                     1.15.3           py36ha559c80_0    defaults
numpy-base                1.15.3           py36h8128ebf_0    defaults
numpydoc                  0.8.0                    py36_0    defaults
odo                       0.5.1            py36h7560279_0    defaults
olefile                   0.46                     py36_0    defaults
openpyxl                  2.5.9                    py36_0    defaults
openssl                   1.0.2p               hfa6e2cd_0    defaults
packaging                 18.0                     py36_0    defaults
pandas                    0.23.4           py36h830ac7b_0    defaults
pandoc                    2.2.3.2                       0    defaults
pandocfilters             1.4.2                    py36_1    defaults
parso                     0.3.1                    py36_0    defaults
partd                     0.3.9                    py36_0    defaults
path.py                   11.5.0                   py36_0    defaults
pathlib2                  2.3.2                    py36_0    defaults
patsy                     0.5.0                    py36_0    defaults
pep8                      1.7.1                    py36_0    defaults
pickleshare               0.7.5                    py36_0    defaults
pillow                    5.3.0            py36hdc69c19_0    defaults
pip                       10.0.1                   py36_0    defaults
pkginfo                   1.4.2                    py36_1    defaults
pluggy                    0.8.0                    py36_0    defaults
ply                       3.11                     py36_0    defaults
prometheus_client         0.4.2                    py36_0    defaults
prompt_toolkit            2.0.6                    py36_0    defaults
psutil                    5.4.7            py36hfa6e2cd_0    defaults
py                        1.7.0                    py36_0    defaults
pyasn1                    0.4.4            py36h28b3542_0    defaults
pyasn1-modules            0.2.2                    py36_0    defaults
pycodestyle               2.4.0                    py36_0    defaults
pycosat                   0.6.3            py36hfa6e2cd_0    defaults
pycparser                 2.19                     py36_0    defaults
pycrypto                  2.6.1            py36hfa6e2cd_9    defaults
pycurl                    7.43.0.2         py36h74b6da3_0    defaults
pyflakes                  2.0.0                    py36_0    defaults
pygments                  2.2.0            py36hb010967_0    defaults
pyhamcrest                1.9.0                    py36_2    defaults
pylint                    2.1.1                    py36_0    defaults
pyodbc                    4.0.24           py36h6538335_0    defaults
pyopenssl                 18.0.0                   py36_0    defaults
pyparsing                 2.2.2                    py36_0    defaults
pyqt                      5.9.2            py36h6538335_2    defaults
pysocks                   1.6.8                    py36_0    defaults
pytables                  3.4.4            py36he6f6034_0    defaults
pytest                    3.9.1                    py36_0    defaults
pytest-arraydiff          0.2              py36h39e3cac_0    defaults
pytest-astropy            0.4.0                    py36_0    defaults
pytest-doctestplus        0.1.3                    py36_0    defaults
pytest-openfiles          0.3.0                    py36_0    defaults
pytest-remotedata         0.3.0                    py36_0    defaults
python                    3.6.6                hea74fb7_0    defaults
python-dateutil           2.7.3                    py36_0    defaults
python-libarchive-c       2.8                      py36_6    defaults
pytz                      2018.5                   py36_0    defaults
pywavelets                1.0.1            py36h8c2d366_0    defaults
pywin32                   223              py36hfa6e2cd_1    defaults
pywinpty                  0.5.4                    py36_0    defaults
pyyaml                    3.13             py36hfa6e2cd_0    defaults
pyzmq                     17.1.2           py36hfa6e2cd_0    defaults
qt                        5.9.6            vc14h1e9a669_2    defaults
qtawesome                 0.5.1                    py36_1    defaults
qtconsole                 4.4.2                    py36_0    defaults
qtpy                      1.5.2                    py36_0    defaults
requests                  2.19.1                   py36_0    defaults
rope                      0.11.0                   py36_0    defaults
ruamel_yaml               0.15.46          py36hfa6e2cd_0    defaults
scikit-image              0.14.0           py36h6538335_1    defaults
scikit-learn              0.20.0           py36heebcf9a_1    defaults
scipy                     1.1.0            py36h4f6bf74_1    defaults
seaborn                   0.9.0                    py36_0    defaults
send2trash                1.5.0                    py36_0    defaults
service_identity          17.0.0           py36h28b3542_0    defaults
setuptools                40.4.3                   py36_0    defaults
simplegeneric             0.8.1                    py36_2    defaults
singledispatch            3.4.0.3          py36h17d0c80_0    defaults
sip                       4.19.8           py36h6538335_0    defaults
six                       1.11.0                   py36_1    defaults
snappy                    1.1.7                h777316e_3    defaults
snowballstemmer           1.2.1            py36h763602f_0    defaults
sortedcollections         1.0.1                    py36_0    defaults
sortedcontainers          2.0.5                    py36_0    defaults
sphinx                    1.8.1                    py36_0    defaults
sphinxcontrib             1.0                      py36_1    defaults
sphinxcontrib-websupport  1.1.0                    py36_1    defaults
spyder                    3.3.1                    py36_1    defaults
spyder-kernels            0.2.6                    py36_0    defaults
sqlalchemy                1.2.12           py36he774522_0    defaults
sqlite                    3.25.2               hfa6e2cd_0    defaults
statsmodels               0.9.0            py36h452e1ab_0    defaults
sympy                     1.3                      py36_0    defaults
tblib                     1.3.2            py36h30f5020_0    defaults
terminado                 0.8.1                    py36_1    defaults
testpath                  0.4.2                    py36_0    defaults
tk                        8.6.8                hfa6e2cd_0    defaults
toolz                     0.9.0                    py36_0    defaults
tornado                   5.1.1            py36hfa6e2cd_0    defaults
tqdm                      4.26.0           py36h28b3542_0    defaults
traitlets                 4.3.2            py36h096827d_0    defaults
twisted                   18.9.0           py36he774522_0    defaults
typed-ast                 1.1.0            py36hfa6e2cd_0    defaults
typing                    3.6.4                    py36_0    defaults
unicodecsv                0.14.1           py36h6450c06_0    defaults
urllib3                   1.23                     py36_0    defaults
vc                        14.1                 h0510ff6_4    defaults
vs2015_runtime            14.15.26706          h3a45250_0    defaults
wcwidth                   0.1.7            py36h3d5aa90_0    defaults
webencodings              0.5.1                    py36_1    defaults
websocket-client          0.53.0                py36_1000    conda-forge
werkzeug                  0.14.1                   py36_0    defaults
wheel                     0.32.2                   py36_0    defaults
widgetsnbextension        3.4.2                    py36_0    defaults
win_inet_pton             1.0.1                    py36_1    defaults
win_unicode_console       0.5              py36hcdbd4b5_0    defaults
wincertstore              0.2              py36h7fe50ca_0    defaults
winpty                    0.4.3                         4    defaults
wrapt                     1.10.11          py36hfa6e2cd_2    defaults
xlrd                      1.1.0                    py36_1    defaults
xlsxwriter                1.1.2                    py36_0    defaults
xlwings                   0.12.1                   py36_0    defaults
xlwt                      1.3.0            py36h1a4751e_0    defaults
xz                        5.2.4                h2fa13f4_4    defaults
yaml                      0.1.7                hc54c509_2    defaults
zeromq                    4.2.5                he025d50_1    defaults
zict                      0.1.3                    py36_0    defaults
zlib                      1.2.11               h8395fce_2    defaults
zope                      1.0                      py36_1    defaults
zope.interface            4.5.0            py36hfa6e2cd_0    defaults</code>
</p></p>
