By default, when you double-click on a font in Windows, it gets installed in the %localappdata%\Microsoft\Windows\Fonts directory. Unfortunately, translationStudio Windows doesn't seem to check this directory for fonts. The workaround is to install the fonts directly to the C:\Windows\Fonts directory. However, one can't just drop the font file into this directory, as Windows Explorer will re-route it to the user's AppData directory instead.
Open a Command window as administrator. Then, use copy «font name» C:\Windows\Fonts to copy the font to the proper location. A reboot is not necessary for this to work, although you'll probably have to quit translationStudio and restart it if it's running at the time.
For Mac users, the same problem can be resolved by copying the font to /Library/Fonts.
For Linux users, install the font to /usr/share/fonts/truetype. Although the other fonts in this folder are in subfolders, don't do that for the fonts you install, as translationStudio will be unable to find them.
