The date that is stored in the file is of an incorrect format. This causes Glyphs to crash.
Did you use any tool other than Glyphs to create or edit the .glyphs file? That might have corrupted the .glyphs file. Or maybe this is an edge case where an old version of Glyphs wrote an incorrect format.
Anyway, I will look into it. In the meantime, you can fix such corrupt .glyphs files by opening them in an plain text editor (like Text Edit, not like Word or Pages) and fixing the date like so:
before:
date = "2022-02-27 11:10:24 p. m. +0000";
after:
date = "2022-02-27 23:10:24 +0000";
Or send the files as a private message and I’ll send you the fixed version back.
Thank you so much! It worked. I tried with another file and changed the date, and it worked!
I wonder if it’s possible to make Glyph to save it in a 24 hour clock format by default, because apparently the 12 hour clock format it was the cause.