How do you install new fonts to adobe illustrator

Try checking out this link – covers several Window's OS Options.

https://www.fontspring.com/support/installing/how-do-i-install-fonts-on-my-windows-pc

I have a font in .OTF format that fails to be installed on my WIndows 10 box for no clear reason ("not a valid font file"). THe very same OTF file works OK on Linux and Windows 7.

A workaround how I managed to work with this font on my Illustrator CC 2018 was to copy this OTF file to C:\Program Files\Common Files\Adobe\Fonts\ and since then the Adobe CC can succesfully open files using this font. THe font is not visilble for the rest of the OS but I don't care as I need to use it only in some Illustrator documents.

Exquisite directions, Ray.

I'm not great on computers but here is how I do it --on windows 7

You will need to download a small program to unzip the file first - as it sounds like your  computer does not have one already.

You can google 'file unzipper' or  file extractor and find one for yourself or try

this one, it's well know, free and safe, although your security still might warn you a little ..

http://www.7-zip.org/

When you have downloaded  it, or another similar one , run the set up and it will install itself on your computer.

Then start it up

If you cannot find it look in Start > All programs > 7 Zip > 7 Zip file Manager

From the above  find the file and unzip it - extract it -

One way to do this,  is from  the above window    Tools >  Options >

then   7-ZIP

It's the options that are going to appear in the context menu ie what you'll see you right click a file.

Tick, for example Extract here ,OK

Then you go to your new font file you  downloaded,

place it in its own folder, to keep everything  tidy.

Right click on it , look for 7-zip and select Extract Here

it will open the zipped file up ,now choose the  font file  eg the one   ending in       .ttf

right click on that  and  use Windows Install.

Then it should add it to your system , ..