“Error: Cannot find Java 1.8 or higher”
You checked and you have Java 1.8 or higher installed, right? (if not, to do that — that’s the problem).
This error usually happens on Windows and there’s an easy solution. Go to the Gephi folder in your Applications folder. If you’re on windows 10, look in C:\Program Files (x86)\Gephi-0.9.1\bin\
There will be two versions of Gephi in there. They are probably called gephi.exe and gephi64.exe. Try them both. One of them will probably work for you.
The Graph Disappeared!
You’re going along fine when all of a sudden, there’s just a big grey space where the graph used to be! It will look something like this:
Do not panic and please do not uninstall and reinstall Gephi (the thing students do most before asking me). All that happened here is that you accidentally closed the graph window. Go to the Window menu at the top and select Graph and it will come right back:
Note that this works for all kinds of things that seem to have disappeared. If you can’t find the layout section or the Appearance, you probably closed it by accident. Just go to the Window menu and pick the thing you need and it will come back on the screen.