Is there a script to clear font cache at shutdown or boot?

Okay. I haven't tallied them up in quite a while, so I'll assume 2 and 3 are only the fonts installed by the OS. No third party fonts added to the Library or System folders.

But yes, third party fonts are any you've installed that are not included with the OS. Somewhere in that group of 1454 active fonts are ones that are conflicting with other fonts, or are damaged. Clearing the cache temporarily solves the issue. Any bad fonts that are active then once again damage the cache and you're right back where you were.

You can start by replacing your library with known good, fresh copies. If after that the issue continues, then you need to try and weed out the bad ones.

It's not fun. You activate about 20 at a time and see what happens. If good, activate another 20. If things go bad, at least one font of the last group activated is bad. Turn those off and activate smaller groups of that 20 until you've narrowed it down to the culprit(s). Delete the ones causing the problem.

As you can guess, this can take at least hours, if not days to sort through 3000 fonts.

Are you using the most recent Font Explorer X Pro recommended for Mojave?

Seems to me that it would be a common denominator for recurring font cache issues, or deactivated fonts that are required by the operating system. Booting into Safe Boot mode also rebuilds the System font cache. Those question marks appearing in emails and Quick Look could be expected Mac fonts that you have deactivated, and the font replacement is breaking.

There are no scripts to clear font cache, but there are Terminal commands for that purpose.

Here is a living document about macOS fonts by Kurt Lang, and in particular, review the section on How to handle font caches. It talks about Font Explorer X.

Hello Leah,

very thorough and VERY long, and way more than I care to know about this.

Aw, but fonts are fun! 😁

The basic problem is you likely have at least one conflicting font somewhere. The OS then gets confused which is the correct font, and the font cache data gets mangled because the OS is trying to save a cache for duplicate fonts. The OS doesn't know what to do, so you then get the boxed question mark from the font, LastResort. You clear the cache, it's fixed momentarily, but the cache gets corrupted once again with conflicting data.

You may not see any fonts with the same Finder name, but it's the internal names of each font that matter. Those are the ones you see in your font lists. You could rename Palatino.ttc to xxx.ttc, and it would still show up in your apps and the OS as Palatino.

Things to do, preferably in the order listed:

a) If Font Book is still on the drive, remove it. Never have more than one font manager on your system at a time. They will fight for control of your fonts. This isn't all that easy to do in Mojave. That is, you can't just move Font Book to the trash since the OS insists it's required by the OS. It isn't. It's just another font manager. The OS will work perfectly fine without it.

How to remove it? Easiest is to startup to any other drive or partition you have the OS on. Once booted to that drive, you can delete anything you want from any other drive. System Integrity Protection only protects the startup disk.

If you can't do that, the next option takes more time, but isn't all that difficult. Restart and hold down the Command+R keys to boot into Recovery Mode. Once at the work screen, go to the top menu bar and choose Utilities > Terminal. In the Terminal window, type …

csrutil disable

… and press return. You should get a message that SIP has been successfully disabled. Then type …

reboot

… and press return. The Mac will restart.

Now, even from the startup drive, you can put Font Book in the trash and delete it using only your admin password. Make sure to empty the trash. Then repeat the steps above for Recovery Mode, except the first command will be …

crsutil enable

You should get a message that SIP has been successfully enabled.

Type reboot and press return. The moment the Mac goes into the restart sequence, hold down the Shift key to enter Safe Mode. This is just to once more delete all user cache files for the account you login to in Safe Mode. Once at the desktop, restart again normally.

Two more things to do related to Font Book before you're done with this first step. Now that Font Book is gone, you want to clear the last of anything related to its startup data.

From the desktop, hold the Option key down and from the top menu bar, choose Go > Library. This opens the Library folder in your user account. From there, open the Preferences folder. Delete these two items (both may not exist):

com.apple.FontBook.plist

com.apple.FontRegistry.user.plist

Lastly, remove all font cache data from the system.

Close all running applications. From an administrator account, open the Terminal app and enter the following command. You can also copy/paste it from here into the Terminal window:

sudo atsutil databases -remove

This removes all font cache files. Both for the system and the current logged in user. After running the command, close Terminal and immediately restart your Mac.

All of this is to get Font Book and its related data off the drive so it stops interfering with FEX. This itself may not fix the visible issue of question marks where text should be, but we're just getting Font Book out of the way. Simply launching Font Book will cause it to recreate the .plist files you removed, and other hidden data. The OS then reads those to determine what fonts Font Book says should be active or not, which may not be what FEX says. This conflict of font management needs to be eliminated.

b) Now test to see if the issue returns. If it does, you have either damaged or conflicted third party fonts installed. Let us know and we'll address it as necessary.

I'm no techy, but I know that's not normal.

It's very normal. There are far more users who are very competent at using a computer, but not really knowing how to fix one than there are tech-heads.

That means, somewhere, you have a conflicting or corrupt font. Or, multiples of them.

If you used Font Book at any time to add fonts to the system, they would go into the Fonts folder of your user account by default. In FEX, you can disable all of these at once by clicking on the expansion arrow next to System Fonts and and clearing the check box by your user name.

Disable any other third party fonts you've added.

Assuming you have added no fonts to the root /Library/Fonts/ folder, or the System's Fonts folder (nothing installed by the user should ever go there), then all that should be left open are the fonts installed by the OS.

After disabling all fonts installed by yourself, clear all font caches once more and test. If the issue returns, then the OS installed fonts are damaged. There is a way to install fresh copies of these without having to reinstall the entire OS.

That's a good plan! Wait until the issue surfaces on its own with only third party project fonts open. You instantly know those are the only ones you need to check, for the moment anyway.

There is another way. You used Suitcase at one time. That automatically gets you a serial number for Font Doctor. FEX has a great built-in function for checking fonts, but Font Doctor sometimes catches errors the other doesn't. Run your entire catalogue of fonts through it and see what it finds. The only thing to lose is a few minutes of time.

Uncertain what is corrupting your font cache per your description, and out of ideas for a permanent fix. I was hoping that Kurt Lang would get involved in this discussion.

You're welcome. 🙂

What Apple's doing for OS security and the user is necessary, and is for everyone's benefit. But the OS is indeed getting much harder to work on from a tech end because of it.