Why Does uBlock Origin Show Increasing Blocked Elements on Outlook.com?

It’s a good point that the site isn’t actually static. Even if you’re not interacting with it, Outlook.com is still generating traffic, uploading telemetry, and downloading ads. If you want to see what's going on, try checking the uBlock logger to get detailed insights.

There are a ton of scripts running in the background that refresh elements, load telemetry, and cycle through ads. UBlock Origin not only blocks ads but also stops trackers and other components from functioning. So, when you notice the block count rising, it’s because these elements are constantly being activated, especially on sites focused on communication and collaboration.

Outlook.com is ad-supported unless you have a Microsoft 365 subscription, so your ad blocker is likely doing its job by blocking ads and possibly other telemetry. With a high count like that, it's probably also blocking some benign diagnostic processes that help the site run smoothly. It’s tough to pinpoint exactly how many elements are being blocked without diving into specifics, but it makes sense that many elements are being filtered out over time.

Each time you get an email, Outlook tries to show a notification, which uBlock blocks. If you leave the tab open, it’ll keep blocking notifications for any replies in email chains or mass emails, leading to a buildup. It's worth noting, though, that you mentioned you weren’t sending or receiving emails during your meeting.