This is a major problem that Outlook.com / Microsoft are ignoring completely. Since they closed the last thread from 2012 without a resolution, I'm opening a new one.

https://answers.microsoft.com/en-us/outlook_com/forum/all/how-do-i-stop-the-spam-from-outlookcom/200b256c-3f58-453f-8bf8-e0cad9bda9f0

I administer a large and active online forum, and recently it has been getting bombarded by forum spam. Virtually all of it comes from accounts that were registered on obviously fake mass-created Outlook.com email addresses (and other Outlook.* international domains). The spam accounts are manually created on my forum and their garbage gets posted by human users, as is apparent from their usage patterns. But the Outlook email registration addresses they use are clearly automated and generated on a massive and virtually limitless scale.

By contrast, I almost never see forum spam from Gmail accounts, because their registration process is difficult and prevents massive automated creation of accounts. Not even the plethora of temporary junk email address providers generate as much forum spam as Outlook.com.

Of course, I have multiple mechanisms in place to control forum spam, including CAPTCHAs and honeypots and IP blocking and community spam moderation. It is principally the forum administrator's responsibility to control spam, and I accept that. But the email providers also need to do their part to prevent abuse.

What's going on Microsoft? Do you approve of forum spam? Do you care about your reputation? Are you happy to be an enabler of this plague that is ruining the internet?