I've two issues regarding fonts, but one is more important than the other - i.e. I've deleted a system font. I'm in a quandary - whilst messing around with fonts, I made a copy folder for my system fonts in case this happened. So, you say, copy them back into the original folder. Ah, but when I try and do that, I get this:- So I'm stuck! I can't do what I want to do, because that particular system font is missing. Does anyone know what it's called? (And it won't let me fill it in with what I know should go in the boxes.) Also, when I look at my Firefox now, I get this bizarre font showing on the tabs and in the location & Google bars (and in some Finder windows):- This is the main issue to be solved. The other issue is Mac fonts generally - I could cry when I install them. No matter how many times I do it, the ones I want just DO NOT appear in my list in Word, PowerPoint etc. - this is so frustrating! I can see them in Font Book, but I just can't use them. I've tried telling Font Book to only use my User Fonts folder and vice versa, but it doesn't make any difference. So I copied all fonts from everywhere into one font copy folder, deleted them everywhere else and reinstalled them. All great - apart from the system fonts of course. (Why do Apple make this so HARD? Even Windows fonts made more sense than this!) Therefore I need some urgent help for item one, please - and possibly for item two, if anyone can explain this. (In words of one syllable please, and speak slowly as if to a very old person - when I look at other replies to problems here, I just don't understand the terminology sometimes - sorry! ) Thank you SO much! PS. Before this happened, I checked (or thought I had) the system fonts list with the list here:- OS X: Fonts included with Mavericks - but I must have inadvertently missed one out?