Is the a limit of installed fonts PowerPoint on MacOS can handle?

Kris Sowersby

Is the a limit of installed fonts PowerPoint on MacOS can handle? 

We spent a long time troubleshooting a customer’s font not showing in PowerPoint. (Clearing caches, restarting, new fonts, etc).  They ended up “fixing it” by deactivating everything but system fonts and ours — hey presto they worked. So, is there a hidden font limit for MS Office apps?

John Hudson

I think there is, but I don’t have details. On my old computer, where I had a lot of fonts installed via Font Book, MS Word fairly recently started showing a warning that not all my fonts could be loaded, and I noticed a specific few not available in the Word font menu. I don’t remember this in older versions of Word, so my suspicion is that this is related to Microsoft’s font service, possibly with the intent of encouraging users to employ fonts from the service against local installation, and possibly misapplied on Mac OS. In other words, this might be the outcome of a string of misapprehensions.

Will try to find out more information.

Floor van Steeg

This might not be related, but if the apps are Sandboxed (this is a requirement when distributing from the Mac App Store), there is a limit to the number of files an app can access at once. Loading activated fonts counts towards this limit if not explicitly unaccessed by the app. You may notice that you also cannot open/save files when the limit is reached by that application.

As far as I know the number of files an app can access is constrained by kernel memory. It depends on the machine, and also where the accessed files (fonts) are located. So it's hard to tell what the exact limit is. According to my tests this starts around a few thousand (3k+) activated fonts.

Clearing the cache should typically help, because this deactivates the fonts. Unless the font files are stored in one of the macOS font folders (e.g. `/Users/<username>/Library/Fonts`) in which case they're all activated again immediately after restarting.

I haven't tested if this is the case for the Office apps, but I know it may cause trouble in other macOS applications. If the applications are not sandboxed, which I believe the Office apps weren't before distributing through the App Store, then they shouldn't have this limit.

John Hudson

Interesting observations, Floor. Thanks.

In my case, I didn’t get the Office apps through the Mac App Store, but direct from the Office 365 site. Not sure whether that would make a difference in this case.

Mark Simonson

FWIW, MS Office apps are also available outside the app store. You can get a subscription to Office 365 directly from Microsoft (which is what I do). I don't think this version has the same sandbox limitations.

Kris Sowersby

Looks like the limit is 1,000 fonts:

http://www.jklstudios.com/

“The Office apps don’t crash, they simply cut off the number of fonts shown at about 1,000. You always see all of the OS system installed fonts and the ones within the Office application packages. From there, Office starts alphabetically with your third party fonts and displays their names up to the limit. Anything beyond that is not shown.”

Can anyone here from Microsoft confirm this? It would be nice to have open communication about how the Office apps actually deal with fonts. 

Floor van Steeg

If it's exactly 1000 fonts and it's always this exact limit, then it sounds like it's hardcoded into the Office apps. If it changes depending on the Mac and depending on which fonts are activated, then it's most likely not a deliberate constraint, as I can't imagine they've set a random limit. Official confirmation would indeed be nice.

The Office apps outside of the App Store might also be Sandboxed (it's not exclusive to the App Store, it's just a requirement). To verify if the apps are Sandboxed you can use https://mothersruin.com/software/Apparency/ (choose File > Open from the main menu and open the PowerPoint.app — the right panel shows if 'App Sandbox' is enabled.) 

Mark Simonson

Indeed, it's also sandboxed. Never mind.