Sending, receiving, and organizing email in Outlook on the web for business
I have the same problem. If you look to the top right of the screen, there is a button that says select. You now have to click on that, then the select all button appears next to the delete button.
Absolutely infuriating that what was once a single click to select all, is now a two step process.
Microsoft - this is a bad change. It complicates the process. Please change it back.