I just installed Zorin OS 18 core and Gparted was absent from the menu and when I tried installing in terminal, it said it was already installed. When I tried running it it was not found. The following procedure fixed everything.
1st uninstall
sudo apt remove gparted
2nd uninstall dependencies
sudo apt autoremove
3rd reinstall with dependencies
sudo apt install -f gparted
Now it shows in the start menu and runs as expected.