When I start Muse the Start Screen appears as expected. But it is empty. Nothing appears under RECENTS or CC FILES. Nothing under the Learn tab either. As a final insult both the NEW and OPEN buttons are dead. (I can create new and open sites using the menus). I am logged in with my Adobe ID.
I uninstalled and re-installed through the Creative Cloud app. Nothing changed. This is a life-or-death matter--just annoying. Start Screen works fine with other apps.
Many apologies for all the trouble.
I have got this bug to be fixed in next release.
This mainly happens if Muse is installed at non-default location (not in C:\Program Files).
Please make sure that install location is set to "default" in your Creative Cloud app as per below instructions.
Uninstall and reinstall Muse, let me know how it goes.