OUCH! But that upgrade over one 7 install didn't go so well! First a look a the report!
Microsoft pushes Windows 10 upgrade to PCs without user consent
Confirms it has been silently downloading massive upgrade to Windows machines via automatic updates, chewing up bandwidth and storage space
By Gregg Keizer
Computerworld|Sep 11, 2015 12:59 PM PT
Microsoft today confirmed it has been pre-loading the Windows 10 installation bits onto devices whose owners have not "reserved" a copy or expressed interest in the new OS.
The move has upset some users of Windows 7 and Windows 8.1, who have complained that the unsolicited downloads have caused them to exceed their Internet providers' data caps or seized storage space without their consent.
In a statement, Microsoft acknowledged the practice, which was first reported by The Inquirer on Thursday.
"For those who have chosen to receive automatic updates through Windows Update, we help customers prepare their devices for Windows 10 by downloading the files necessary for future installation," a company spokeswoman said in an email. "This results in a better upgrade experience and ensures the customer's device has the latest software. This is an industry practice that reduces time for installation and ensures device readiness."
If Windows 7 or Windows 8.1 device owners have Windows Update set to the default -- and Microsoft-recommended -- option that lets the operating system download and install security and other bug fixes automatically in the background, Microsoft will push the Windows 10 upgrade files to the drive.
see report in full
So why didn't 10 simply upgrade over 7 automatically? Well in Windows 7 the option of checking for and prompting the user or never are two alternative options to prevent updates from simply going on automatically without prior notification. The manual check on the 10 app suddenly one day(Sept. 1st) start downloading the previously reserved in mid June copy but too late! 10 was already set up in a dual boot with 7.
Others report finding 10 had already gone on from having left everything to the automatic setting. How to prevent an unplanned or unwanted upgrade especially if you already have 10 set up in a dual boot situation? The Windows Update setting in the Control Panel are the place to start. The solution here will be the already scheduled need for a long over due clean install of 7 first getting things on 10 organized a bit?
But what if the 10 app returns for some reason afterwards? Well 10 has already been released since the app was first seen prior to 10's launch date. A clean install on a second machine of 7 Pro so far hasn't even seen the 10 app appear as that was seen to after the launch date. Keeping the option to never or with 8 or 8.1 the option to defer updates or schedule restarts preferred and recommended are one way to prevent the automatic upgrade over the previous version if you trying to keep a dual boot or simply not ready to upgrade to 10.