Today python encounter this problem in the installation of some packages (xgboost, mlxtend) time.
The method according to other blog, such as https://blog.csdn.net/miao0967020148/article/details/85230430 can be solved, but every time you install a new package will have this problem, and finally read some other blog, it should be the path there is no need to install the add channel packages where the lead can be completely resolved by the following methods:
Terminal type codes:
conda config --add channels conda-forge
And through conda or pip install packages they need no longer be a problem.
Note that channel is not necessarily conda-forge, depending on the type you need to install the package, belong to that specific package types can be viewed through the code:
anaconda search -t conda package to be installed
Of course, if you need to install the package less can also operate directly in accordance with the method given blog linked above :)