Some users complained that Windows 10 automatically installs without their permission. This issue is common among Windows 7 users.

Bt.com reported that users ranted about the issue on social media and forum sites such as Reddit. Some occurrences included computers to crash, or the Windows 10 forced upgrade started while users were doing something important.

Redditor LhoT10820 was one of those who first warned others about the Windows 10 forced upgrade. Apparently, his father's computer was "bricked" by the said upgrade.

His post has since received comments from other users who have experienced the same Windows 10 forced upgrade.

"Yep this happened to me this morning," Geekygirlhere wrote on Reddit. "Working and all of a sudden Windows closed all my programs, logged me out and started the upgrade. I quickly shut down my computer and was able to stop it but my son wasn't so lucky. Same thing happened to him today."

However, Microsoft denied the complaints about the Windows 10 forced upgrade.

"Customers continue to be fully in control of their devices, and can choose to not install the Windows 10 upgrade or remove the upgrade from Windows Update (WU) by changing the WU settings," Microsoft told The Inquirer.

According to Tech Times, Microsoft announced that Windows 10 will be a "Recommended Update" beginning 2016. This would mean that the user's Windows Update settings may trigger the upgrade automatically.

"Before the upgrade changes the OS of your device, you will be clearly prompted to choose whether or not to continue." Microsoft posted on its blog. "And of course, if you choose to upgrade, then you will have 31 days to roll back to your previous Windows version if you don't love it."

Venture Beat reported that Microsoft's executive vice president of operating systems, Terry Myerson, promised developers that Windows 10 will soon be on 1 billion devices within the next few years.