Just downloaded and tried TT7 beta and I had a few issues.
First, like some of you, I opened a template made with latest v6 version and could not export, using .zip file or folder. When I tried many times, the software just crashed. Exporting a template created from scratch worked.
I tried to save my template, and reopened it after the crash and I got this (it is a VM + Joomla template) :
Lastly, I don't know if it is normal or not, but when I opened the About us menu, I got this :
Thank you and regards,