i have a late 2011 MacBook pro running OS Sierra 10.12, and i want to install windows 10 OS on it. review showed that OS Sierra will not accept earlier versions of window. is this possible?

Sierra 10.12.2 corrected the bug which forced W10 on Macs which did not support it. Now, Sierra will let you install W7/W8.1 on supported models as noted in Download macOS Sierra 10.12.2 Combo Update .

I have Windows 7 in bootcamp on the other half of the hard drive. I did it years ago though. I would advise to use bootcamp with an earlier OS, and then install windows, then update your Mac OS. If you are Willing to go through all of that.

Sierra is not the problem, the problem is that for a new install of win 10 you need, if a MacBookPro, a mid 2012 or newer one.

Use Windows 10 on your Mac with Boot Camp - Apple Support

You can get Win 10 by installing an earlier Windows version and updating it.

You also need to consider possible driver issues since 2011 Macs do not officially support W10.

Please see macOS Sierra: Revert to a previous macOS version . You need to use a Time Machine backup.

i have the same issue , till the new update in windows 10 it was working fine but now it does not support windows 10, i am looking for the answer that how to reinstall windows 10 on mac OS X sierra but it show that it does not support windows 10 any more. its been a month i am trying to solve this issue. boot camp does not support, edit the plist.info to change the option on boot cam, to install windows 8.1 again also not supported. i don't know where to go and solve this issue.

lovingcheeta wrote:

i have the same issue ...

On 2011 and older models, upgrading to Sierra disallows any version of Windows being installed. This is a known bug. Please downgrade to El Capitan and try to install Windows.