Microsoft has reclassified the Ask Toolbar as unwanted software, which means its security tools will automatically detect and remove all versions, except for the most recent, from Windows computers. The toolbar modifies web browsers, not only by adding itself to the browser s toolbar, but changing the default search engine to Ask.com. Microsoft said Windows Defender for Windows 8.1 and Microsoft Security Essentials for Windows 7 and Windows Vista will detect the toolbar. The decision has been cheered by security and privacy professionals given that the toolbar is not only considered invasive, but also causes a performance drain on browsers.
Source: https://threatpost.com/microsoft-classifies-ask-toolbar-as-unwanted-software/113299/