How do I completely remove mega sync client
Solution 1:
You have in your home directory a megasync configuration ~/.local/share/data/Mega Limited. Configurations in your home directory are not deleted by simply uninstalling a package.
Remove this folder with:
rm -rf ~/.local/share/data/Mega\ Limited
For the future use purge instead of remove when you want config files to be gone as well.
Solution 2:
To clear the mega client configuration must be eliminated.
sudo apt-get --purge remove megasync
and then delete the configuration
rm -rf ~/.local/share/data/Mega\ Limited