How can I block emails with no sender?

While it should not be possible, it seems that some nefarious person has figured out a way to send an email without a sender. I've been getting 1 or 2 a day and looking at the raw headers, they seem to originate from Outlook/Exchange (see attached). I think that I've hidden my email address in the red boxes. What bothers me is that in order to "junk" the email, one has to click on it. I wouldn't be at all surprised that there is code embedded in the message body that sends back to sender, "Yay! We got another one! Keep them coming." One cannot set up a mail rule to move these to junk automatically because one needs to put something in the "From" box.

I receive 50 of these per day and I am on a mac sierra and can only update to big sur. Seeing you cant fix it with big sur, I dont know how to get rid of this garbage. I will say this is only happening on emails that are on Roadrunner email. tampabay.rr.com in my case. Apple iCloud mail doe not receive it.

When you say only two people have this. No many millions have it on Roadrunner email addresses is what I was told and Charter or Spectrum doesnt care about it because email to them is their lowest priority. They have said they wished every email customer would get another provider and that is quoting them. Anyone have any success with blocking the no sender mail? Please respond .thanks

The "no Sender" email issue is NOT just experienced by a few people - it is ubiquitous. I get about 5 a day, plus every person I know also gets them. Please work on a solution that will block such emails.

I think we have a winner! I received 3 more "no sender" emails overnight and they all got sent to my junk mail folder, while legit emails were in my inbox. As someone later suggested, filtering on no "@" should work too. Just make sure that once you create the rule that you enable the rule by checking the box to the left of the rule in the rule list.

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I suggest sending all the junk emails to Apple iCloud as spam. It takes time, but apple needs to fix this issue for their users. I am about to go to some other mail app and can iCloud mail. When I did this I did see a drop in junk/spam emails, but the 268 that I received today, many of them "blocked" ( which doesn't seem to make any difference) perhaps if they are overloaded with the junk emails they'll do something about it. very disappointed in Apple. I was forced to upgrade to a new computer as they changed their software so many sites could not be signed on to. I would like to figure out how to do away with all of it.

I had the same issue of course as everyone else. I figured out how to create a rule that blocks these and sends them to the deleted file so you never see them. I would suggest you call Apple and tell them you want to create a rule to send these emails to the trash or deleted folder so you never receive them again. They have things in common and you must write the rule to block the things they all have in common. I had to play with it a while to come up with the right definition for the rule but it works every time and the problem is gone. I can post the actual rule here, but I would rather recommend that you call Apple instead and let them tell you how to set it up. It is very logical, but it took me weeks to figure out how to do it. Don't lose hope if you have this issue. It can be resolved very easily once you think about it.

Good luck, Charlie

Good question. I haven't tried this since I added filters via my imac for all ISP accounts but if you have ONLY an iPhone this may help. I have not used it myself:

https://clean.email/how-to-filter-emails/iphone-email-filter#:~:text=Open%20the%20Mail%20app%20on,filters%20and%20iPhone%20Mail%20rules.

You can check the full data for a boatload of information

Show detailed headers in Mail on Mac - Apple Support

Do 1.

Is there any text in the body of the emails that you can use to create a rule to move them to the Trash mailbox?

I occasionally get a no sender email but am able to delete it with a keystroke combination with Keyboard Maestro. I don't rely on a rule for that particular spam.

Tell Apple what new features added to the system via Feedback - macOS - Apple.  

I suspect you'll get junk with any email system. The key is how you manage it. With filters and rules, you can keep it to a minimum.