Exporting error message - 'unkown file type'

I’ve just spent all day making a font and now Glyphs keeps crashing when I try to export as a TTF, and when I try just exporting as an OTF, I get an error message that says ‘MAKE OTF ERROR - Unkown file type’

and ideas what the problem is?

can you send me the .glyphs file (to support [at] this domain)?

Perhaps empty out your Temp folder and try again. You can access it via Scripts > Open Scripts Folder.