Outlook.com Rules and Mail Filtering with Aliases

A client reported that rules he had set up on Outlook.com didn’t appear to be working. He wanted to automatically filter email sent to two different aliases of his account (admin@ and mail@). The rules he set up were configured to move all emails with admin@<his domain> or mail@<his domain> in the recipient into the relevant folders, the only problem was that matching emails were going into his Inbox and not being filtered at all.

After some trial & error, I found a solution. The mails appeared to treat the destination mailbox (not the alias) as the recipient, so in order for the rule to work I had to set it to match text in the message headers rather than the recipient field. After that filtering worked as expected.