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Fonts on many websites show up as a question mark in a box.

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running Firefox 57.0.1 on an macOS Sierra 10.12.6. Many websites I can't see the fonts, it shows up as question marks within a box. I have the box checked for allowing websites to choose own fonts. Everything works in Safari, only Firefox has this issue. Fonts in system folder have not been deleted or moved. If I can't get this worked out I guess I'll just continue to use Safari.

running Firefox 57.0.1 on an macOS Sierra 10.12.6. Many websites I can't see the fonts, it shows up as question marks within a box. I have the box checked for allowing websites to choose own fonts. Everything works in Safari, only Firefox has this issue. Fonts in system folder have not been deleted or moved. If I can't get this worked out I guess I'll just continue to use Safari.

Chosen solution

When did this problem start for you?

On Mac, Firefox 56 ratcheted up the security sandbox, limiting which files pages can use on your system. This apparently prevents Firefox from using font files in a "suitcase" or "Adobe Type 1" format. The developers are aware of this and some fixes were made in Firefox 57, but they might have missed some font types or unexpected font file locations.

To see whether this is the problem, and as a temporary workaround, you can reduce the sandbox security level back to what it was in Firefox 52-55 as follows:

(1) In a new tab, type or paste about:config in the address bar and press Return. Click the button accepting the risk.

(2) In the search box above the list, type or paste sand and pause while the list is filtered

(3) Double-click the security.sandbox.content.level preference and change the value from 3 to 1 and click OK

That change won't take effect until the next time you quit and restart Firefox.

Does that let Firefox show website fonts normally?

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All Replies (4)

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Chosen Solution

When did this problem start for you?

On Mac, Firefox 56 ratcheted up the security sandbox, limiting which files pages can use on your system. This apparently prevents Firefox from using font files in a "suitcase" or "Adobe Type 1" format. The developers are aware of this and some fixes were made in Firefox 57, but they might have missed some font types or unexpected font file locations.

To see whether this is the problem, and as a temporary workaround, you can reduce the sandbox security level back to what it was in Firefox 52-55 as follows:

(1) In a new tab, type or paste about:config in the address bar and press Return. Click the button accepting the risk.

(2) In the search box above the list, type or paste sand and pause while the list is filtered

(3) Double-click the security.sandbox.content.level preference and change the value from 3 to 1 and click OK

That change won't take effect until the next time you quit and restart Firefox.

Does that let Firefox show website fonts normally?

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This worked! Thank you so much. Will this be fixed with the next update?

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Hi nazkey, I'm not sure. Apparently fonts are drawn from various unexpected locations and those need to be accounted for. Hopefully someone else can update us on what will be added next or where to find your font locations to provide information to solve it.

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In another thread, user SurfinSpots pointed out that Mozilla has provided steps to capture more information on why the fonts are not loading. However, I admit I don't totally understand the instructions because I have very little Mac experience.

https://wiki.mozilla.org/Security/Sandbox#Debugging_Features