One developer to me:
I will need access to root account on that new machine you just installed so that I can install/configure all the stuff and so you won't have to do it.
Me - I can't give you root. Not even sudo, this will be a production machine, I need to have a clean track of it.
D - but I will give it (root) back to you once I'm done.
Me - look pal, root access is like virginity. I can give it away but I will never be able to get it back.
D - But you can remove my access later. And, talking about virginity, there are operations that "restore" virginity ;)
Me - yes, and I can take access to root from you afterwards, which would be similar to the procedure you are referring to. But it won't change the fact that the server was already fucked.

tldr := Windows 10...
So I had Windows 8.1 / Linux dual boot system. And decided that, what the heck, I'll try upgrading to WinX. That went well. Surprisingly. I even used WinX for a while. Windows 10 and linux side by side, on the same disk, just different partitions. And since everything was so nice, I've decided to let Windows install some updates. After reboot, uefi linux entry is gone. What? How? Well, after update windows found 'unrecognized' partition, and, since it is urecognized, it must be unused. So it helpfully fucked it up. That was linux uefi partition (yes, I kept them separate).
Long story short, windows8.1 back from original image, side by side with linux. Lesson learned, gonna ispect each windows update twice before installing. And not gonna touch WX even with a 10-foot stick!