I've reproduced your problem. I installed Fedora-Workstation-Live-x86_64-25-1.3.iso
on a system, then did;
sudo dnf groupinstall sugar-desktop
.
Starting Terminal and typing sugar
did not work. Prompt returned with no error, but exit status 1. Looking at log file .sugar/default/logs/shell.log
there is a missing package, which could be fixed with;
sudo dnf install webkitgtk3
Caused by the Fedora package of Sugar not declaring a dependency. After start, sugar
did work once.
But on logout gdm would not show a Sugar desktop entry, and the GNOME desktop would no longer work. It would not start, as you saw.
After applying all updates with dnf update
, the login screen gdm itself would not work.
You might take this further with Fedora. It looks much too fragile to be used.