Browser maker Mozilla isn’t happy with Microsoft’s decision about resetting the default browser.

A week ago, Mozilla CEO, Chris Beard, has taken his exasperation in public. He decided to write an open letter to Satya Nadella, chief executive of Microsoft, taking aim at the company’s policy on handling changes that were made to the default applications in Windows 10. He called it “disturbing” and slammed the tech giant for making an aggressive move of designating its Edge as a default browser.

Beard was referring to the Windows 10 upgrade setup process. Here, users who simply clicked on the “Next” button in the express setup will automatically have Edge as their default browser even if they have previously used Google Chrome of Mozilla Firefox.

This rubbed Beard the wrong way since most users will choose the express settings just because it’s easier. Although users are eventually given the chance to re-assign Firefox of Chrome as their default browser, many of whom will be unlikely to bother. This task would be difficult for majority of users and would just end up abandoning the process.

Beard said in the letter, “I am writing to you about a very disturbing aspect of Windows 10. Specifically that the upgrade experience appears to have been designed to throw away the choice your customers have made about the Internet experience and they want, and replaced it with the Internet experience Microsoft wants them to have.”

Beard also said that his company has reached out to Microsoft to address this problem prior to Windows 10 release, but this attempt of opening communication lines has landed on deaf ears; hence this letter.

To make it easier for users to change their default browser, Mozilla posted a tutorial which includes step-by-step instructions on how to restore Firefox as their default browser. The same instructions can also be used by users who wish to assign Chrome or Opera as their default.