When you do a fresh install of the Windows 10 Insider Build 17063, users run into a screen without a skip button and demands the user to give their phone number. This isn’t the first time Microsoft has been asking the user for their phone numbers but usually users could skip this step. All of this could be related to Microsoft’s new push to convince Windows users it can help them resume activities and apps even if they’re using an iPhone or Android device. The current state of affairs is only for Insider builds and Microsoft has not confirmed anything about a public release demanding your mobile number. It will surely spark a new privacy controversy if Redmond decides to make mobile numbers mandatory for all windows 10 users.