There's no any link or button to click to open the attachment file.
I can't open an attachment file. All I can do now is forwarding the mail to Gmail and then open it in Gmail. I don't know why you broke this again, it happened before.
Thank you for your feedback. We appreciate that you took the time to write to us.
You might enjoy the new Outlook experience more with a few changes to your settings, which you can find by clicking the gear icon. Try changing the setting for Conversation view to Off, changing the setting for Reading pane to Hide, and changing the setting for Attachment preview to Off.
We’re always interested in new ideas, but we need some more specific feedback to fix the problem for you. If you have more detailed suggestions, please update your idea or add a new one.
You might also find this help article useful: aka.ms/outlookcombetahelp. It has some simple steps to fix common problems.
-The Outlook.com Team