If you have a ton of feeds, this could also theoretically speed up Outlook—at the very least it makes your system a little cleaner.

Note: If you aren’t using Internet Explorer or Outlook as a feed reader, you could simply delete all of the RSS feeds.

Disable Outlook Common Feed RSS Sync

To turn this off, go to Tools –> Options from the menu and click the Advanced Options button on the Other tab.

  

Now you can uncheck the item “Sync RSS Feeds to the Common Feed List”.

Now that you’ve disabled the Sync feature, you can delete all of the feeds from under the RSS Feeds folder.

You’ll probably want to also empty your Deleted Items folder after removing the feeds.