New Windows 10 Insider Preview Fast Build 18312 (19H1) - Jan. 9 Insider

@JGToy:
That phenomenon sounds like a virus infection of some kind, and in any case highly mysterious.

sgage said:

I dual boot mainline and Insiders builds, on the same physical drive, and haven't had much problem. If I were you, I'd make sure to have a Macrium rescue USB on hand. If you boot with that, under 'restore' is an option to 'fix Windows boot problems'. This has never failed to straighten things out for me. If your new instance of Windows takes over the boot process, and you don't want that, you can always fix it in options at the boot screen.

Yeah, that's solid advice. That was definitely the one situation I wanted to avoid. I do have a Macrium rescue usb. So I will keep it handy if needed for this very thing. Thanks again for all of your help. One last question, do you use Rufus to make your bootable usb? That's what I've always used. But since I haven't done this in years, I'm not sure if there's a better option now, or if most people still use Rufus.

Kari said:

My point was, although you do not like it, that TenForums is a global site. Although we all write here in English, and assume everyone is using a 64 bit W10 PRO in English, that's not the case with some (most?) of us.For instance, I although using English Windows, I would not like to have it in colonial English, so called EN-US. I want my Windows to be in real English, so called EN-GB.Posting a link like "Here's W10 ISO for you" does tell nothing to me. Is it in my preferred language, is it my preferred edition, is it my preferred bit version?That was my point. Anyway, as anyone can make the ISO by themselves, I find the links to ISO files made by someone else quite useless.Kari

Dude, who pied in your wheeties??? Why go on a rampage in response to someone doing a kindness for someone else? YOU didn't ask for the iso, I did. So he was responding to ME! Do you get that? He see's that I AM in the USA, so no need for all the crap you are asking for. We get that you guys have a chip on your shoulder because of the general dominance of the USA in the world, but there's no need to jump on a guy who was just doing another user a kindness. It had nothing to do with you.
Here we have sgage, Wynona and myself sharing a nice moment of helping each other and refreshing information that hasn't been used in a while, and you pitch a temper tantrum over something you weren't a part of. Try to relax and be kind to others, instead of always looking for a reason crap on something...

smactilactus said:

Yeah, that's solid advice. That was definitely the one situation I wanted to avoid. I do have a Macrium rescue usb. So I will keep it handy if needed for this very thing. Thanks again for all of your help. One last question, do you use Rufus to make your bootable usb? That's what I've always used. But since I haven't done this in years, I'm not sure if there's a better option now, or if most people still use Rufus.

I still use Rufus - it just works for everything I throw at it. Just download the latest version - works fine for burning Windows iso's.