I know mac users don't have this issue, but for windows users: you shouldn't be installing fonts directly into the fonts folder. Use a font manager like fontbase. Just put all your typography in a single folder, link it to the manager, and you can toggle fonts on and off with one click. If a font file happens to be corrupted, installing it directly risks ruining your windows base fonts and corrupting your photoshop/illustrator. Having too many fonts installed makes your software laggy and miserable to use. Just turn the fonts on when you are working on a specific design, and toggle them off when youre done. The files don't take up much space so you can keep them, just don't leave them installed eternally.