That is quite large. A 1GB STL could easily make a gcode file that is several GB, which requires even more GB of memory to preview. Most likely your computer runs out of resources at some point, which is why the preview won't show up.
You could try re-meshing the STL file so it is smaller, or go to Tools > Options and disable the "automatically load preview after slicing" option. That way you can export the gcode right away without trying to load a 10 GB preview
