I was typing the 6 letters I had made so far, ABCDE, when I decided to get back to work. So I designed my G, imported the image, still going great, and I saved my font again. When I went to look at it in Windows Font Viewer, I saw othing! It was totally blank!!!
Does your font preview correctly in the Font Test windows (F5) ?
The usual suspect is Windows, as it can become confused if you are testing numerous versions of a font. We know for sure if a reboot solved the issue.