我已经下载了最新的 anaconda，当我想全部更新时，它想删除所有软件包。知道发生了什么吗？
C:\WINDOWS\system32>conda update --all
Collecting package metadata (current_repodata.json): done
Solving environment: done
## Package Plan ##
environment location: C:\Users\marek\Anaconda3
The following packages will be REMOVED:
_anaconda_depends-2019.03-py37_0
alabaster-0.7.12-py37_0
anaconda-custom-py37_1
anaconda-project-0.8.3-py_0
astroid-2.2.5-py37_0
astropy-3.2.1-py37he774522_0
atomicwrites-1.3.0-py37_1
babel-2.7.0-py_0
backports.os-0.1.1-py37_0
backports.shutil_get_terminal_size-1.0.0-py37_2
bitarray-0.9.3-py37he774522_0
bkcharts-0.2-py37_0
blas-1.0-mkl
blosc-1.16.3-h7bd577a_0
bokeh-1.2.0-py37_0
boto-2.49.0-py37_0
bottleneck-1.2.1-py37h452e1ab_1
cloudpickle-1.2.1-py_0
comtypes-1.1.7-py37_0
console_shortcut-0.1.1-3
contextlib2-0.5.5-py37_0
curl-7.64.1-h2a8f88b_0
cycler-0.10.0-py37_0
cython-0.29.11-py37ha925a31_0
cytoolz-0.9.0.1-py37hfa6e2cd_1
dask-2.0.0-py_0
dask-core-2.0.0-py_0
distributed-2.0.1-py_0
docutils-0.14-py37_0
et_xmlfile-1.0.1-py37_0
fastcache-1.1.0-py37he774522_0
flask-1.0.3-py37_0
get_terminal_size-1.0.0-h38e98db_0
gevent-1.4.0-py37he774522_0
greenlet-0.4.15-py37hfa6e2cd_0
h5py-2.9.0-py37h5e291fa_0
hdf5-1.10.4-h7ebc959_0
heapdict-1.0.0-py37_2
html5lib-1.0.1-py37_0
icc_rt-2019.0.0-h0cc432a_1
imageio-2.5.0-py37_0
imagesize-1.1.0-py37_0
importlib_metadata-0.17-py37_1
intel-openmp-2019.4-245
isort-4.3.21-py37_0
itsdangerous-1.1.0-py37_0
jdcal-1.4.1-py_0
joblib-0.13.2-py37_0
jupyter-1.0.0-py37_7
jupyter_console-6.0.0-py37_0
keyring-18.0.0-py37_0
kiwisolver-1.1.0-py37ha925a31_0
krb5-1.16.1-hc04afaa_7
lazy-object-proxy-1.4.1-py37he774522_0 …