Created new user. Tested from it. Guix pull works great. Now will move the stuff. 
Thanks a lot. 

пн, 27 дек. 2021 г., 18:53 Maxime Devos <maximedevos@telenet.be>:
Hi,

Grigory Shepelev schreef op ma 27-12-2021 om 17:27 [+0300]:
> After the last letter my laptop's motherboard broke. It was replaced
> recently but all the data was lost from the SSD due to encryption...
> TLDR: I made a backup and reinstalled the system.
> But the problem still persists. How can I safely move root's profile
> into the user's one?  Tinkering with any root-related things is a
> danger zone for me, so I won't do anything on my own until there are
> any clear instructions.

You could try deleting /var/guix/profiles/per-user/$USER and running
"$THE_GUIX_OF_ROOT pull" and "$guix install ...". I don't see why that
wouldn't work, but I've never tried it and 0 warranty.

> As previously: from root "guix pull" works perfectly. From users it
> has the same problem (nix-related error).

Could you search for "show-derivation" in the back-up? E.g. with grep -
rF show-derivation. Maybe there's a leftover from when you used nix
somewhere ...

Greetings,
Maxime.