^{Originally posted by lesliexia985-alt January 24, 2026}
I am a Fontra user from China. I have been using Fontra for some time to work on my graduate project, which is a Chinese variable font. Fontra has been extremely important for my work, so thank you very much for developing and maintaining it.
However, I am currently stuck with a persistent export error and do not know who else to ask for help. The Chinese Fontra platform stopped operating last year, and I have very limited programming knowledge, so I sincerely apologize in advance if this turns out to be a very basic mistake.

Whenever I try to export my font, the export process fails. Fontra reports that a character causes a KeyError, and the export cannot be completed.Fontra shows a KeyError related to a specific character. The detailed error code is as follows:

INFO:fontra.backends:creating project temp.designspace...
INFO:fontra.backends:done creating temp.designspace
Process Process-15:
Traceback (most recent call last):
File "multiprocessing\process.py", line 314, in _bootstrap
File "multiprocessing\process.py", line 108, in run
File "FontraPakMain.py", line 351, in exportFontToPath
File "asyncio\runners.py", line 44, in run
File "asyncio\base_events.py", line 649, in run_until_complete
File "FontraPakMain.py", line 398, in exportFontToPathAsync
File "fontra_compile\compile_fontmake_action.py", line 79, in process
await copyFont(inBackend, dsBackend, continueOnError=continueOnError)
File "fontra\backends\copy.py", line 37, in copyFont
return await _copyFont(
File "fontra\backends\copy.py", line 88, in _copyFont
raise e
File "fontra\backends\copy.py", line 148, in copyGlyphs
await destBackend.putGlyph(glyphName, glyph, glyphMap[glyphName])
File "fontra\backends\designspace.py", line 729, in putGlyph
glyphSet.deleteGlyph(glyphName)
File "fontTools\ufoLib\glifLib.py", line 550, in deleteGlyph
KeyError: 'uni9E1F'

The project is a Chinese variable font, it works normally inside Fontra (editing, preview, etc.) The error only occurs during export.
So what does this KeyError usually indicate in Fontra?Is there a recommended way to successfully export my font in this situation?

Again, I apologize if this is a simple issue. I am not familiar with programming, and I would be very grateful for any guidance or explanation.