Hi!
Sorry for the late response, I was busy otherwise.
By "then reboot", I meant it rebooted by itself. The first two times I tried the "guix pull".

"How do you start guix-daemon?"
I didn't change any of the defaults regarding this. So I guess the daemon must start at startup with the other daemons.

"guix describe" gives this output:
$ guix describe
Generation 12 mai 31 2020 11:28:03 (current)
  guix 018cffc
    repository URL: https://git.savannah.gnu.org/git/guix.git
    branch: master
    commit: 018cffc9c9e5a5855733f5f45a1c4d396bb6a321


Screenshot from 2020-06-07 03-05-33.jpg

On Thu, Jun 4, 2020 at 8:11 PM zimoun <zimon.toutoune@gmail.com> wrote:
Dear,

On Thu, 4 Jun 2020 at 17:42, Julien Lepiller <julien@lepiller.eu> wrote:
> Le 4 juin 2020 10:38:09 GMT-04:00, "Léon Lain Delysid" <leon.lain.delysid@gmail.com> a écrit :

> >I just tried to "guix pull" on my Debian Buster GNU/Linux system. Twice
> >it
> >made the system completely freeze for a few seconds and then reboot.

What do you mean by "then reboot"?
Does it reboot by itself or do you manually force the reboot?

> >And
> >that third time it didn't crash the system but the guix pull failed and
> >returned this error:
> >https://pastebin.com/vhDR8gDC

How do you start guix-daemon?


> >(Before doing the third "pull", I did an "apt update" and "upgrade",
> >but I
> >wasn't that much behind in updates, I had done it less than a week ago
> >last. My last "guix pull" was made at the same time as the "apt
> >update", a
> >few days ago.)

What is your "guix describe"?

>
> >Hoping I can resolve this soon or that my feedback was positive for the
> >development of Guix. =)
> >I can provide log debug info (if there is any) upon request.
> >
> >Best regards!
>
> Sorry pastebin is not tor friendly, I couldn't look at it.

Julien, here the paste:

--8<---------------cut here---------------start------------->8---
./guix/store.scm:1035:9: ERROR:
  1. &store-protocol-error:
      message: "error parsing derivation
`/gnu/store/m5djg8zwgl7nh0rm1av4nnlbwgwi0fwg-guix-daemon-1.1.0-4.bdc801e.drv':
expected string `Derive(['"
      status: 1
guix pull: error: You found a bug: the program
'/gnu/store/kpxami25fi3mrxb37sfbbx2s366chpk5-compute-guix-derivation'
failed to compute the derivation for Guix (version:
"415b90f24ee83059102f5fb0ce74a2bc0954fe58"; system: "x86_64-linux";
host version: "018cffc9c9e5a5855733f5f45a1c4d396bb6a321"; pull-version: 1).
Please report it by email to <bug-guix@gnu.org>.
--8<---------------cut here---------------end--------------->8---

First time, I see that.

All the best,
simon