How to completely clean your CONDA installation (for beginners) - gecos-lab/PZero GitHub Wiki
If you are re-installing after problems with a previous Anaconda install, use anaconda-clean before uninstalling the previous Anaconda environment:
https://docs.anaconda.com/anaconda/install/uninstall/
From Anaconda prompt (before uninstalling) clean the environments:
conda install anaconda-clean
anaconda-clean --yes
Then uninstall from from Windows > Start > Control Panel > Programs and Features
Then use Windows Explorer to delete old Anaconda folders:
C:\Users<YOUR_USER>.conda
C:\Users<YOUR_USER>.conda_rc
C:\Users<YOUR_USER>.astropy
C:\Users<YOUR_USER>.continuum
C:\Users<YOUR_USER>.designer
C:\Users<YOUR_USER>.matplotlib
C:\Users<YOUR_USER>.ipython
C:\Users<YOUR_USER>.jupyter
C:\Users<YOUR_USER>.spyder-py3
C:\Users<YOUR_USER>\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Anaconda3 (64-bit)
And finally remove all possible keys from the registry with regedit.exe.
These instructions are for a Windows operating system. They can slightly differ for Mac and Linux.