Why am I suddenly receiving spam calendar invitations/appointments in Outlook (Microsoft 365 Family).

I just uninstalled Microsoft Calendar. Problem solved. But I don't understand how things were showing up on my calendar and popping up notifications if I didn't open any emails with such events/attachments.

I use Thunderbird as my email client. Could Microsoft be scanning my messages for calendar events?

Previous questions from 2021 provided responses that "Microsoft is aware of the problem and is working on it". Clearly, they aren't trying very hard. What is also clear is that Microsoft's spam filtering is woefully inadequate.

Does anyone bother to go after the generators of spam? For example, literally EVERYTHING that comes from imgur.com is spam. They are a literal spam factory. Why isn't the FCC or FTC jailing these scammers?

I've had my hotmail account for 24 years now and I've never gotten so much spam in my email or calendar as I have the past couple of months. I have been fighting this calendar issue for over a month now. I can get up to 8 or 10 of these "invites" a day. It has rendered my calendar useless. The spam has also taken over my email account and I am deleting anywhere between 40 and 60 spam emails daily. I have marked them as junk/phishing/spam etc. but they keep coming back. Microsoft used to be good at keeping spam in the junk folders but not anymore. I'm done with outlook / hotmail. I have moved my calendar items already and I will be moving my actual email related accounts over to my gmail account.

I think you didn't understand what is happening. There are no messages or invites that appear in my inbox to categorize as junk. The appointments are going directly to calendar and have to be opened in order to delete them.

So far they are just annoying but whoever is doing this could just as easily send some nasty malware that activates when the appointment is opened.

Exactly, they are coming straight to Calendar as an "Invitation" to a meeting. They are spam, and are most certainly malware/phishing attempts. Unfortunately, there isn't typically a mechanism to just delete it without "declining" the invitation. They have started happening every day on the account that I already get tons of spam on because it was compromised and now appears on the dark web.