New problems with new Outlook. All favorite inboxes have suddenly disappeared, which means I have to recreate them (I have three accounts - one Outlook and two Office 365). Other favorites are missing as well, but they're not as critical. And one of my accounts has spontaneously duplicated, so it now appears twice.
Between these issues and 1) the ongoing lack of a unified inbox, 2) the inability to save attachments properly and 3) no link to the ToDo app (the icon links to the web version), I can no longer use new Outlook as an email client. I am now using Windows Mail, as it at least has a unified inbox and appears to be stable. I still have old Outlook for Office 365, but tasks get corrupted when I use those, so it is not an option either.
I hope someone at Microsoft is looking at these comments, as new Outlook really needs some work to be usable by people who have more complex mail requirements.