Windows takes a long time to boot on 2010 iMac

[glsillygili]

I have an iMac with no screen that I plugged into an external monitor. Mac OS X will boot up fine on it but when I try to boot up windows it sits for at least 10 minutes doing nothing until it finally shows the windows bootup logo and boots up normally. I've installed Windows 7 and Windows 10 and they both do the same thing. Is this because I don't have a internal screen connected?

 

[DaveFromCampbelltown]

It seems a bit strange to be sitting there for 10 mins, then boot up as normal. Mine only sits for a maximum of 20 seconds.
What version of macOS are you running? And what version of the Boot ROM (About This Mac > System Report > Hardware Review) A later version of the OS may upgrade your Boot ROM.

 

[glsillygili]

It seems a bit strange to be sitting there for 10 mins, then boot up as normal. Mine only sits for a maximum of 20 seconds.
What version of macOS are you running? And what version of the Boot ROM (About This Mac > System Report > Hardware Review) A later version of the OS may upgrade your Boot ROM.

I had high sierra installed earlier and now have catalina so that shouldn't be a problem.