Getting a error message on export "Glyph with empty name"

This is my first time using glyphs, so bare with me.
I’ve altered 2 glyphs in the OTF font Lato.
When I go to export to a TTF, I get a error message:

"There is a glyph with a empty name.

Please check the font."

What does this mean and how can I fix it?


there is a glyph in your font that has no name. the easiest would be to switch to list mode and sort by name. Then the empty name should be at the bottom or the top.