Once the font opens in the main editing window, go to the top menu and select .
Use the pyftsubset or a simple script utilizing fontTools.ttLib to unpack the file. convert ttc font to ttf work
Remember: A TTC is not a corrupted TTF; it is a different container format entirely. Treat it like a ZIP file of fonts. Extract the contents properly, rebuild the tables, and you will have a perfect, working TTF every time. Once the font opens in the main editing