CondaValueError: You have chosen a non-default solver backend (conda) but it was not recognized.

最近mamba受欢迎，可以加速环境的配置，在已有的conda基础上安装mamba可能会导致

CondaValueError: You have chosen a non-default solver backend (conda) but it was not recognized. Choose one of: classic

或者

CondaValueError: You have chosen a non-default solver backend (libmamba) but it was not recognized.

等问题的出现。导致conda也运行不了，mamba也运行不了,我尝试了很多方法，包括重新安装conda，都没有作用

我出现这样的问题是通过以下方法解决，在Linux下

vi  ~/.condarc 

将内容改成如下：

auto_activate_base: true
channels:
  - conda-forge
  - defaults
show_channel_urls: true

然后就是安装mamba，要安装并设置新的求解器，现在mamba好像只能安装到base下

conda install -n base conda-libmamba-solver
conda config --set solver libmamba

安装mamba

conda install mamba -n base -c conda-forge

如果还有问题可以去vi ~/.bashrc

将conda初始化改一下，添加mamba

# >>> conda initialize >>>
# !! Contents within this block are managed by 'conda init' !!
__conda_setup="$('/home/anaconda3/bin/conda' 'shell.bash' 'hook' 2> /dev/null)"
if [ $? -eq 0 ]; then
    eval "$__conda_setup"
else
    if [ -f "/home/anaconda3/etc/profile.d/conda.sh" ]; then
        . "/home/anaconda3/etc/profile.d/conda.sh"
    else
        export PATH="/home/anaconda3/bin:$PATH"
    fi
fi
unset __conda_setup
 
if [ -f "/home/anaconda3/etc/profile.d/mamba.sh" ]; then
    . "/home/anaconda3/etc/profile.d/mamba.sh"
fi
# <<< conda initialize <<<

当然，具体的conda路径需要修改一下

此时cat ~/.condarc 可以看到

auto_activate_base: false
solver: libmamba
channels:
  - conda-forge
  - defaults
show_channel_urls: true

mamba超好用！