I have the latest OS, 12.5.1.
The machine is MacBook Pro (Retina, 15-inch, Mid 2015).
I think Apple Silicon is much newer (2020?).
The processor is 2.5 GHz Quad-Core Intel Core i7.
The graphics is AMD Radeon R9 M370X 2 GB.
Sigil-1.9.2 has the same problem. I've tried reinstalling both.
Dragging and dropping does nothing different.
All the menu items appear to respond. If I open a file and do a Save As, the result opens fine in Calibre, but the Sigil window stays blank.
The About Sigil window says:
https://sigil-ebook.com/sigil, GNU Public License v3, Version 1.9.20, Build time 2022.09.01 14:15:42 UTC.
I do not see a way to attach a screenshot of the window. The title bar says (for example) untitled.epub - epub2.0 - Sigil [std]. There is nothing else.
Thanks.