Hi, I've installed Fedora 26 with gnome. sometimes it starts without environment panel, I log in with the user and there is only Desktop background image and mouse. But, sometimes when it starts normally it works. I've tried XFCE and KDE, but the result was the same.

Tell us more about your computer's specifications.

To make sure I understand your issue properly, is it that the panel (sometimes referred to as the taskbar), where the menu, off/on button, etc., are located appears sometimes and not others and that this happens with Gnome, XFCE, and KDE?

I would suggest this: Next time you log in and the panel does not appear, check the logs and save the portion relevant to that startup to a file (they should be time-stamped). Then, the next time you log in and the panel does appear, do the same (or vice-versa). Then compare the two files.

I'm not an expert on SystemD logging by any means, but, in traditional logs, I'd start with /var/log/Xorg.0.log. If rsyslog is installed, you may find that SystemD logs are being exported to /var/log/.

Thank you for the answer, yes when I say panel, I mean icons on desktop or application buttons (There is nothing except background image).

this is the idea to view different log files. But actually I was hoping more concrete answer for example, ' yea, I've had the issue like that and I changed that file'. So, in every case, thank you for the answer, I'll view log files.