Dual boot Win10/Win11 question

Hi. One of my PCs is already set up for dual boot Windows10-21H1/Windows10-21H2. At boot I get a dual boot option, with a timeout for 5 seconds, after which, the PC boots into the default installation of Windows 10. The other instance of Windows 10 is there for various reasons (I won't waste valuable bandwidth explaining them!) but I rarely use it. In any event, as each instance is on a separate physical drive, it's good to know that I can boot into the other, should one drive fail.

I am being asked if I want to upgrade to Windows 11 on both installations. At the moment, I do not want to in so far as the default instance of Windows 10 is concerned (used just for X-Plane - I use another PC entirely for emails, browsing and whatever). I need to check out in more detail what might 'break'; first.

I am thinking of accepting the upgrade on the second installation of Win10 to Win11 however, (which I don't use for anything really, and is pretty much 'vanilla'), just so as I can start familiarising myself with it.

My question then (finally) is: if I do go ahead and upgrade the 'vanilla' Windows 10 installation to Windows 11, is this in any way going to affect the way the dual boot works? Is the PC looking for two instances of Windows 10, so that changing one to Windows 11 is going to mess things up? Or will I just see the same boot option when I start the PC? (I think the dual boot was set up with EasyBCD, which is fairly user-friendly as far as I recall).

Probably straight forward, but I want to know what to expect before I do anything., rather than get a nasty surprise

Thanks.

It will upgrade only that Windows 10 to Windows 11 and it will leave the other Windows 10 as is. It will likely change your dual booting to make Windows 11 the default and change the timeout back to 30 seconds, which are both easy to fix.

It will likely change your dual booting to make Windows 11 the default and change the timeout back to 30 seconds, which are both easy to fix.

.. via EasyBCD I guess. I will still see the two boot options though when I start the PC.. just that Windows 11 may be the system into which the PC boots if I don't intervene?

martinlest said:

.. via EasyBCD I guess. I will still see the two boot options though when I start the PC.. just that Windows 11 may be the system into which the PC boots if I don't intervene?

Yes.

OK, maybe I'll go for the upgrade when I am next offered it. Will post back here if it all goes pear-shaped! Thanks.

Well, fate intervened (before I read your post dalchina). I booted into the 'vanilla' Win10 and was offered an 'upgrade' to Windows 11, so I went ahead with the update. Several minutes to download and then the PC rebooted itself. The boot menu was unchanged and when I went back to the O/S I had supposedly changed to Windows 11, and that is unchanged too. Same desktop etc. and the PC Info page still shows Windows 10 Pro, as before. No error messages or the like. So what is going on, do you think?

I have now 'upgraded' the second O/S to Windows 11 (the Windows update finally ran OK). I ended up with a load of EFI boot entries though - but managed to remove them via bcdedit /delete (cmd window), as explained elsewhere. (Found I had to turn off the PC and restart it, not select reboot, for this to work). Why did this happen? They weren't there before of course.

I can now start to familiarise myself with the 'delights' of Windows 11... no rush!

Thanks again to those who replied here.