Bad font detected error

Ash_13's Avatar


13 Jul, 2018 08:36 AM

When I go to "", the error message
"Bad font detected"(translated from Japanese to English, because my machine is in Japanese) popped up.
All Japanese characters disappear, remaining some words in Latin alphabets.
(Refer to attached img 1)
Clicking "Inspect element" in context menu, and I searched about font, I've found sentence included Japanese font like this.
<link rel="stylesheet" href="//,v1:200,300,400,500,600|SF+Pro,v1:200,300,400,500,600|SF+Pro+Icons,v1" type="text/css" media="all" />

Similar phenomenon occurs in Adobe site "".
A uppercase letter "A" in a square appears everywhere. (Refer to attached img 2)
I've found this line in a site source.

Sorry for my poor English!

iBook G4 1.33GHz
Mac OS X 10.4.11
TTF 7450 FPR 8

  1. Support Staff 1 Posted by Cameron Kaiser on 13 Jul, 2018 04:32 PM

    Cameron Kaiser's Avatar

    Thank you for the detailed report. Certain webfonts are known to be incompatible with 10.4 and 10.5. Unfortunately, due to other limitations, it is not possible to detect them automatically. We maintain a blacklist of bad fonts, and the browser will select an alternative with the same character.

    Using the steps in this earlier support ticket, are you able to find the font URL that causes the problem for you? I can make a guess from the Apple URL, but not the Adobe one. If you can provide both, I will add them to the internal blacklist for the next release of TenFourFox.

  2. 2 Posted by polluks on 13 Jul, 2018 04:47 PM

    polluks's Avatar

    My 10.5 shows no message box but the text also disappears.
    Workaround: Press Esc in time.

  3. 3 Posted by Ash_13 on 14 Jul, 2018 12:51 AM

    Ash_13's Avatar

    Cameron Kaiser
    Thank you for your quick reply!
    I'll follow your instruction tomorrow, because I need to go out today.

    Thank you! I'll try it!

  4. 4 Posted by Ash_13 on 15 Jul, 2018 12:51 PM

    Ash_13's Avatar

    I have followed your instructions, these URL I found.

    Apple site ""

    adobe site ""
     I can't find any URL Box of defective fonts on Adobe site.
     But 2 fonts didn't appear "Abc"s, and these fonts are below.
     (I attached a screenshot. "Img 3")

     5b235c75970f368b20501ab5c318ba905cbb46575db6c176291b0f59a298cf0b Regular system
     Used as: "adobe-clean-han-japanese"

     2fceb24a56890659f77dad252b9a548499b117d5d8798f4a71314cced0c2101d Regular system
     Used as: "adobe-clean-han-japanese"

    If there is a shortage of information, please let me know.

  5. Support Staff 5 Posted by Cameron Kaiser on 15 Jul, 2018 09:52 PM

    Cameron Kaiser's Avatar

    The Apple URLs will be blocked. Thank you for performing those steps.

    The Adobe one is a weird case. It's actually being loaded over JavaScript. I suspect the URLs are coming from Typekit, but I'll need to do some additional investigation. This problem is now being tracked as issue 513:

  6. 6 Posted by Ash_13 on 16 Jul, 2018 02:36 AM

    Ash_13's Avatar

    Thank you, Cameron!

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