I can't use "remove" to uninstall xtreme download manager
It seems to be installed completely in /opt/xdman, with xdman.desktop copied to /usr/share/applications/and creating a symbolic link /usr/bin/xdman. So, to completely remove/uninstall, you should remove the link, the desktop file and the installation directory:
sudo rm /usr/bin/xdman
sudo rm /usr/share/applications/xdman.desktop
sudo rm -r /opt/xdman
This should do it.
There is a straightforward answer here now (tested only on Ubuntu 16.04.3 LTS/elementary OS 0.4.1 Loki though :) )
- Open Terminal
cd /opt/xdman/sudo ./uninstall.sh
That's all ;)