The firm started by Bill Gates, PICTURED ABOVE, has triggered some controversy with Windows 10
Windows users who have opted-in for automatic updates on their Windows 7 or Windows 8.1 machines might be in for a nasty surprise.
Your PC could be losing gigabytes of space to make way for Windows 10 installer files, quietly being downloaded onto your machine by Microsoft.
The Redmond technology firm, which released its Windows 10 operating system earlier this summer, has admitted it downloads the files "just in case".
Windows 10, which unites the Microsoft ecosystem across a host of devices including smartphones, tablet and desktops PC, first rolled out back in July.
More than 75million devices across the globe are now running the new operating system.
But now the US company has decided to start preparing the upgrade process on users' computers, without them being aware.
Microsoft confirmed the move to technology blog The Inquirer after one of their readers noticed that a 3.5GB folder had appeared on their computer overnight.
A spokesperson for Microsoft told the site: "For individuals who have chosen to receive automatic updates through Windows Update, we help upgradable devices get ready for Windows 10 by downloading the files they’ll need if they decide to upgrade.
"When the upgrade is ready, the customer will be prompted to install Windows 10 on the device.”
Microsoft is currently running a year-long promotion which allows people running genuine copies of Windows 7 and Windows 8 to upgrade to Windows 10 for free.