This Windows 10 feature is creating a lot of controversy by Michal Addady @FortuneMagazine July 31, 2015, 11:54 AM EDT E-mail Tweet Facebook Linkedin Share icons Windows 10 was released earlier this week, and its launch turned out to be very successful, garnering about 14 million users within the first couple of days. There have been a few controversial features so far, including a hidden fee and an unhelpful error message, but the one that people are most upset about is a feature that quietly changes your default browser for you. When you upgrade to Windows 10, your default browser will automatically be changed to Edge if you choose the “express settings” option, ignoring the preferences that you had previously chosen. There is an option to maintain your old browser, but you have to click the button that says “customize settings,” which is much smaller than the express option, and then click another button later on to actually enable customization (hint: if you put on your reading glasses, you’ll find it at the bottom left of the screen). You can change your settings after you’ve upgraded to Windows 10, but it’s not easy. Supposedly, it takes much more effort and technical sophistication than previous versions. Chris Beard, Mozilla’s CEO, is particularly displeased by this “aggressive” action, which is expressed in both an open letter to Microsoft’s CEO as well as a blog post calling for them to fix the issue. He is appalled by Microsoft’s MSFT infringement on their users preferences, and writes: The update experience appears to have been designed to throw away the choice your customers have made about the Internet experience they want, and replace it with the Internet experience Microsoft wants them to have…. Please give your users the choice and control they deserve in Windows 10. Sign up for Data Sheet, Fortune’s daily morning newsletter about the business of technology.