People throughout the industry are reporting phishing notices in a lot of mail going through Microsoft properties this morning. I even got one in an email from one of my clients earlier today

Multiple people have talked to employees inside Microsoft, and I suspect their customers have been blowing up support about this. I know they’re aware, I suspect they’re frantically working on a fix.
Update 11 am PDT: It appears this filter is firing when mail has the word “hotmail” in it. This includes if non displaying text (like CSS) has the word in it. It feels like they were attempting to mitigate something and wrote a rule that wasn’t quite right. Still no word on a fix, but don’t panic.
Update 12:30 PDT: Reports are that the warning is gone. No word from Microsoft, but as long as things get fixed we don’t need it.

Microsoft • MSN/Hotmail • outlook.com