spam from <preview@***> where the *** part changes each time

Thanks for the excellent answer. And, as you may know, these emails go in cycles. I used to get hundreds of "renew@XXX". Those finally went away, followed by "Preview@XXX". Others with different sender name are dropping in to.

Too bad Microsoft does nothing about it. But I also agree that the US Government needs to get involved. I spend a lot of time going through my junk email looking for legitimate emails mixed in with all the BOT emails.

As someone who tests software for a living, I can say with certainty that this is an attack specifically aimed at Outlook and no other service. The reason for it is because of how Microsoft set up Outlook to only block domains on their Junk Folder. This means a botnet can send crazy amounts of phishing emails using phony domains without having to change the prefix on an email address and there's no way for users to block any of it. The fact that it goes directly into the Junk Folder is by design from this particular hacking group. What they're hoping for is someone will click on one of the two links they have in their emails accidentally when they go to try and delete them.

It's clear to me that Microsoft doesn't seem to see this as a threat to their users and believe it to be an inconvenience that they can let go without consequence. Given the nature and danger of this particular attack, this is being grossly misjudged. These emails are dangerous and need to be blocked such that they never get to the Junk Folder. It does make me wonder if there's a way to get US federal regulators involved to force MS to do the right thing and protect its users from harm.

Either way, this whole thing has been extremely disappointing to me. I've used Outlook and Microsoft 365 (PAID) for years and this is the first time I feel like I don't matter as a customer. It's not fun having to spend chunks of my day scanning through all those "preview" emails in my Junk Folder to make sure nothing legitimate has made it into there. It used to be about 4 emails per hour. It appears to have increased over the last week or so. Probably because this hacking group managed to increase the size of its botnet.

One more person here with the exact same issue.

Since this seems to be an Outlook specific issue not happening anywhere else, it leads to the conclusion that Microsoft is either technically not able to, or (worse?) unwilling to resolve its customers problems?

I don't know if this will help you, but I found a rule that directs all of those to the junk folder, but I have specified in the rule to permanently delete them but it doesn't work. it is so frustrating and really ticks me off, I'm tired of the bs. Apply this rule after the message arrives to where my name is not in the To box and with "preview or new or info or office or medhireuniversity in the senders address and permanently delete it. except where my name is in the to box stop processing more rules. I have the enable rules on all messages downloaded from RSS feeds checked.

I also have a problem with an email getting permanently deleted that i want. So I marked the sender as safe, but it still gets permanently deleted every date. These reply messages from microsoft also end up permanently deleted.

The rule would work, if it worked. LOL I'm no expert on outlook, so if anyone can find my error with the rule please let me know, otherwise I'm going to abandon this email and start over.

After months of having this problem of dealing with my crummy outlook email client, I’ve dumped it and installed Thunderbird were there is a junk e-mail filter that actually works. I use microsoft as an email server only! Thunderbird is superior in every way, runs on desktop, not online ****. Keep outlook to wait until microsoft fixes the problem which should be around 2056. Say so long to preview@