Warning to users of Multiple Inboxes, the New Gmail Inbox type looks like it will not allow you to revert back to your old view!

It looks like the ‘Classic’ view, which was needed to enable the Multiple Inboxes Lab, has been retired, making it impossible to go back. However, it looks like if you don’t try out the New Gmail Inbox, you should be ok (for now, at least).

But there is a solution. To solve this issue, return to the ‘Inbox’ section of your Gmail settings and de-select all of the check-boxes for the new Gmail tabs in the ‘Categories’ section.