I know, I know. Arial, blah blah. But I have used it on a TON of stuff in the past. Just upgraded to CC from CS 5. I opened a document and it says arial is missing. I checked out my font management software and I don't see it in there (even though Arial should show up anyway from the system in CC). So, I found Arial and added it to my font management and activated it. STILL doesn't show up in CC. Any thoughts? I'm using Suitcase Fusion 4, InDesign CC on OS X 10.11.5 El Capitan.
Clean your ID preferences and then install the font in a usual way. Still if you dont find it then:
You can go to the same location as Indesign application. Find the fonts folder and add the font to the indesign Fonts folder.InDesign can almost always see fonts present in the Fonts folder.
Extra: you can also put an alias (shortcut) to a folder of fonts
Hopefully this solves your problem