No characters are displaying in Calibre Viewer / Editor

CharlieX · 10-09-2025, 11:53 AM

This is Calibre 8.12 on MacOS 15.7.1 I've only recently upgraded to Calibre because of the platform restrictions.

Unfortunately, there is a problem with the reader so that all glyphs are rendered as errors. This is not a Calibre version issue as I've just checked on another machine with 7.26 and the problems are the same.

I'm enclosing a screenshot demonstrating the issue: I can't even choose a different font!

kovidgoyal · 10-09-2025, 11:56 AM

You have a corrupted font on your systemuse fontbook to locate and remove it.

KevinH · 10-09-2025, 01:36 PM

Yes and duplicate font files can cause the same thing. Try turning off you local fonts first this can help easily eliminate most duplication.

CharlieX · 10-10-2025, 04:57 AM

I have removed all duplicate fonts but the problem persists. Which font does Calibre want to use here?

kovidgoyal · 10-10-2025, 07:57 AM

This isnt calibre using a font its Qt Webengine (the html rendering library the viewer uses) and I have no idea how it picks a font on macos but if you search for this same issue in the forums you will fid posts by other peopl who have fixed it by removing the corrupted fonts.

JSWolf · 10-10-2025, 08:00 AM

Quote:

Originally Posted by CharlieX

This is Calibre 8.12 on MacOS 15.7.1 I've only recently upgraded to Calibre because of the platform restrictions.

Unfortunately, there is a problem with the reader so that all glyphs are rendered as errors. This is not a Calibre version issue as I've just checked on another machine with 7.26 and the problems are the same.

I'm enclosing a screenshot demonstrating the issue: I can't even choose a different font!

I know that ChareInk7SP works and is not corrupted. Give it a try. YOu can download ChareInk7SP from https://www.mobileread.com/forums/sh...d.php?t=184056

CharlieX · 10-10-2025, 08:17 AM

Thanks, but I don't think it's anything to with "corrupt fonts". However, the solution seems to be to reset fonts using the MacOS Font Book. Important: this will remove any fonts installed by the user, though these will be moved from `~/Library/Fonts` to `~/Library/Fonts Removed` and can be added back one by one.

CharlieX · 10-10-2025, 08:22 AM

Thanks but I'm assuming there's some kind of conflict between a user-installed typeface and a system one, though removing duplicates didn't help. Resetting fonts - removing user ones – does solve the problem.

KevinH · 10-15-2025, 06:38 PM

Yes, that is what I said. Newer versions of macOS include fonts many people have previously installed as a user. In my case it was Microsoft fonts like Times New Roman and Arial which Apple replaced with newer system versions that have larger unicode coverage).

Apple's font program calls them "duplicates" but Apple's automatic font fix does *not* work as it has no permission to remove or move system fonts. That is why I recommended removing the user installed fonts to prevent the duplication. And that does work.

10-09-2025, 11:53 AM	#1
CharlieX Junior Member Posts: 4 Karma: 10 Join Date: Oct 2025 Device: Kobo Aura One	No characters are displaying in Calibre Viewer / Editor This is Calibre 8.12 on MacOS 15.7.1 I've only recently upgraded to Calibre because of the platform restrictions. Unfortunately, there is a problem with the reader so that all glyphs are rendered as errors. This is not a Calibre version issue as I've just checked on another machine with 7.26 and the problems are the same. I'm enclosing a screenshot demonstrating the issue: I can't even choose a different font! Attached Thumbnails

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10-09-2025, 11:56 AM	#2
kovidgoyal creator of calibre Posts: 45,592 Karma: 28548962 Join Date: Oct 2006 Location: Mumbai, India Device: Various	You have a corrupted font on your systemuse fontbook to locate and remove it.

10-09-2025, 01:36 PM	#3
KevinH Sigil Developer Posts: 9,062 Karma: 6361556 Join Date: Nov 2009 Device: many	Yes and duplicate font files can cause the same thing. Try turning off you local fonts first this can help easily eliminate most duplication.

10-10-2025, 04:57 AM	#4
CharlieX Junior Member Posts: 4 Karma: 10 Join Date: Oct 2025 Device: Kobo Aura One	I have removed all duplicate fonts but the problem persists. Which font does Calibre want to use here?

10-10-2025, 07:57 AM	#5
kovidgoyal creator of calibre Posts: 45,592 Karma: 28548962 Join Date: Oct 2006 Location: Mumbai, India Device: Various	This isnt calibre using a font its Qt Webengine (the html rendering library the viewer uses) and I have no idea how it picks a font on macos but if you search for this same issue in the forums you will fid posts by other peopl who have fixed it by removing the corrupted fonts.

10-10-2025, 08:17 AM	#7
CharlieX Junior Member Posts: 4 Karma: 10 Join Date: Oct 2025 Device: Kobo Aura One	Thanks, but I don't think it's anything to with "corrupt fonts". However, the solution seems to be to reset fonts using the MacOS Font Book. Important: this will remove any fonts installed by the user, though these will be moved from `~/Library/Fonts` to `~/Library/Fonts Removed` and can be added back one by one.

10-10-2025, 08:22 AM	#8
CharlieX Junior Member Posts: 4 Karma: 10 Join Date: Oct 2025 Device: Kobo Aura One	Thanks but I'm assuming there's some kind of conflict between a user-installed typeface and a system one, though removing duplicates didn't help. Resetting fonts - removing user ones – does solve the problem.

10-15-2025, 06:38 PM	#9
KevinH Sigil Developer Posts: 9,062 Karma: 6361556 Join Date: Nov 2009 Device: many	Yes, that is what I said. Newer versions of macOS include fonts many people have previously installed as a user. In my case it was Microsoft fonts like Times New Roman and Arial which Apple replaced with newer system versions that have larger unicode coverage). Apple's font program calls them "duplicates" but Apple's automatic font fix does not work as it has no permission to remove or move system fonts. That is why I recommended removing the user installed fonts to prevent the duplication. And that does work.