Microsoft has begun testing promotions for some of its other products in the File Explorer app on devices running its latest Windows 11 Insider build.
The new Windows 11 "feature" was discovered by a Windows user and Insider MVP who shared a screenshot of an advertisement notification displayed above the listing of folders and files to the File Explorer, the Windows default file manager.
As shown in the screenshot, Microsoft will use such ads to promote other Microsoft products, for instance, about how to "write with confidence across documents, email, and the web with advanced writing suggestions from Microsoft Editor."
As you can imagine, the reaction to this was adverse, to say the least, with some saying that File Explorer is "one of the worst places to show ads," while others added that this is the way to go if Microsoft wants "people ditching Explorer for something else."
BleepingComputer also tried replicating this on a system running the newest Windows 11 Insider build, but we didn't get any File Explorer ads.
This can likely be explained by Microsoft running an A/B testing experiment trying to gauge the success of such a feature or by the company disabling it after the visible user outcry.
This is not the first time Microsoft added promotional messages to File Explorer, as in 2016, Microsoft also showed a OneDrive ad in the Windows application.
However, Redmond didn't stop with File Explorer, and tested ads pushing its free Office web apps in the menu bar for the Windows 10 Wordpad application two years ago, a campaign with similar user protests.
The company also started displaying ads for Microsoft Edge in the Windows 10 Start Menu every time users searched for a competing browser, prompting them to download the new Microsoft Edge.
Some of these tests also had unintended consequences, with Microsoft breaking the Windows Start Menu and Taskbar while testing a Microsoft Teams promotion on Insiders.
Brandon LeBlanc, Windows Senior Product Manager at Microsoft, told BleepingComputer that "this was an experimental banner that was not intended to be published externally and was turned off."
Update 3/14/22 18:48 EST: Added File Explorer ad from 2016.
Update 3/15/22 14:25 EST: Added Microsoft's statement.