If you are getting notifications from TaskCentral, then your Mac is infected with adware. TaskCentral is adware for Mac.
TaskCentral changes setting in your Mac. First, TaskCentral installs a browser extension in your browser. Then, after TaskCentral hijacks your browser, it modifies settings in the browser. For example, it changes the default home page, modifies search results, and displays unwanted pop-ups in your browser.