New Windows 10 users are beginning to pile up. After releasing a free downloadable upgrade in 190 countries on July 29, it took just 24 hours for 14 million users to make the switch. And according to a report from BGR, the number of new users has just pushed past the 27 million mark.

Microsoft doesn’t expect the interest to die out any time soon. Windows fans are upgrading at an unprecedented rate, and are extremely excited about some of the new features the operating system has to offer.

Windows 10 may be extremely popular with Microsoft fans, but Mozilla CEO Chris Beard recently blasted the upgrade for issues with the platform’s default web browser settings. Beard states that when users install the upgrade, those who choose the “express” setting will have their defaults and file associations deleted, and replaced with Microsoft’s own applications.

This means that Mozilla fans will be greeted with Microsoft Edge as their web browser after upgrading. Mozilla reached out to Microsoft to address the issue, but received no response.

The installation issues don’t seem to be hindering new downloads at all. A Microsoft spokeswoman stated that Windows 10 was designed to give users a simple upgrade experience, and web browser issues aside, the new operating system appears to be a hit.