The revelation was discovered by Twitter user Florian Beaubois, a Windows 11 user that also holds a Microsoft MVP certificate. In a tweet, Beaubois noted “Some people will go mad if Microsoft starts adding ads in explorer,” and showed an image he captured of a banner ad appearing at the top of a File Explorer window. The ad in question read “Write with confidence across documents, email, and the web with advanced writing suggestions from Microsoft Editor.” It also included a “Learn more” button and an “X,” presumably to dismiss it. The tweet immediately earned considerable attention, like most discoveries of ads showing up in traditionally ad-free software do. Microsoft quickly responded to Beaubois’ discovery, with senior program manager Brandon LeBlanc, telling The Verge “This was an experimental banner that was not intended to be published externally and was turned off.” As The Verge itself noted, LeBlanc’s statement did not in any way preclude the possibility that the experimental banner will make a return in the future. This means it’s entirely possible Windows 11’s File Explorer might serve as a new venue for Microsoft advertising. If this does become the case, it won’t exactly be unprecedented. Microsoft has run ads across multiple Windows generations in locations like the lock screen, start menu, taskbar, and even in Windows 10’s own File Explorer. It must be said that most of these ad placements also earned considerable ire, despite generally being easy to close or dismiss. For most of its existence, Windows was exclusively paid software. Now that Microsoft has provided several generations of free, sequential upgrades for the operating system, it might not be surprising that it’s exploring new methods of revenue generation that leverage the OS. Windows 11 users will have to wait and see if the apparent backlash from this accidental discovery is enough to discourage Microsoft from moving forward with any plans to permanently bring banner ads to File Explorer.