Did you sign up for a free copy of Windows 10? Are you running a Windows 7 or Windows 8 PC? Then you could be in for a big surprise: Windows 10 may have already started downloading to your PC…

Microsoft MSFT +2.1%’s stealthy download uses a secret folder – C:\$windows.~BT – and it can be found by opening File Explorer and going to: Organize > Folder Options > View > Show hidden files, folders, and drives.

Read more – When ‘Free’ Windows 10 Becomes Expensive, You Must Know This

Windows 10 is a significant download of almost 6GB which means you can right click on the folder to see how far it has progressed.

That said the size of the download has also prompted some users on capped broadband plans to complain that they have no control over when the new operating system downloads. Something which is also a complaint with its forced automatic updates once up and running.

The flipside to the argument is stealthily downloading Windows 10 to computers over days or even a week means Microsoft can distribute it more smoothly. This is important when it has stated a long term goal of getting Windows 10 onto over one billion PCs. It also reduces the bandwidth crush on launch day had it opted for manual downloads, especially with Microsoft belatedly admitting some users may have to wait weeks.

Of course whether you should be part of the day one upgraders is open to debate.

Windows 10 finally strikes a strong balance between the familiarity of Windows 7 and the advances of Windows 8, but a major upgrade is already planned for October (likely called ‘Windows 10.1’) and the initial release is far from bug free.

Have you taken the plunge to immediately upgrade to Windows 10 and, if so, have you noticed it downloading into its secret folder? Let me know.

For those who remain undecided, here is my detailed guide: Windows 10: Should You Upgrade?