The iMac is running El Capitan (10.11.3) and doesn't support a full Windows 7 download. Can you use a Windows 7 product key to install Windows 10 using an unused Win. 7 product key?
iMac, OS X El Capitan (10.11.3)
What is the year/model of your iMac? Depending on your model/year, W7 is supported. 2015 Macs do not support W7.
Please also see Install Windows 7 and earlier on your Mac using Boot Camp - Apple Support .
Yes you can use your windows 7 product kettle activate Windows 10. But only if it unused
Late 21.5 inch 2015 iMac (10.11.3)
Ok, thanks.
You can install W10 and have 30 days to activate. You can download W10 ISO from https://www.microsoft.com/en-us/software-download/home . You may need to call Microsoft or use their online activation to get the W10 installation to accept W7 key.
You can also try the suggestion from James1232 and check if the W10 will accept the W7 25-character key. It has not worked for me in the past.
Can you use a Windows 7 product key to activate Windows 10 on a Mac?
