What could be wrong when in an empty file, Node tree works like it should, but in my project it doesn’t? If using Viewer node in project files, then it shows mesh.
My project file:
Empty file:
Empty file:
Just to make sure: do you have the modified object enabled in view at all? You’re in “Local” right now - is it still not showing up in normal view? (hotkey - /).
Thanks a lot 
! Many hours thinking here and You make this working!
I don’t understand still what was wrong. I gone back to seeing all with / , but nothing happened. But when selecting any other objects, this Geometry nodes object appeared!?
Now that I look closer, I see it says “(Viewer)” on your first screenshot, so you had an active Viewer Node somewhere off-screen. It probably wasn’t connected to any geometry, so it didn’t show anything…
But when you selected other objects, it stopped previewing through that node. It’s the same for a new project - the Viewer Node is just disabled by default.