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.
Hi and welcome to the forum.
Sometimes good to simply use the Zorin Menu Search box, in this case type gparted, to find installed apps that are hard to find in the menu's.
I did try that. It wouldn't show up even with search. The only way I could determine that it was on the system was when I tried to install with apt, it said it was already installed.