Configuring preferences and options in Outlook.com
I have been getting the same pop-up exactly - for the last several weeks 3-4 time per day for my 2 different Office 365 email addresses.
My IT person has run every scan he knows of and found nothing amiss.
Have you found out anything new for TechNet forum?
I have clicked it, but it just opens up my Windows Explore so I can brows my folders. It doesn't take me to any where that I can do anything to change a password or even enter any info at all.
GoDaddy suggests that it might be a keystroke reader.