Illustrator essentially won't let me create any new files, unless from presets on the main screen upon application launch. Whenever I open the "Create new" dialog (as shown in attached image), it's simply blank. The software is on the most recent version (25.2.3), and I have tried uninstalling and reinstalling on my computer, and the same issue persists.
Can you open the preferences and then turn on the Legacy New dialog box?
It is a workaround (maybe): Preferences > General > Use legacy "New File" interface.
This does allow me to make new files until the larger issue is fixed, thanks.
Have you tried a uninstall and a reinstall?