Thank you, Ludovic, for your attention. That exact. New try gave acceptable result. And now I am able to keep trying to configure touchpad tap... https://lists.gnu.org/archive/html/help-guix/2018-10/msg00137.html # guix pull Updating channel 'guix' from Git repository at 'https://git.savannah.gnu.org/git/guix.git' ... Building from this channel:   guix      https://git.savannah.gnu.org/git/guix.git     a961ae4 Computing Guix derivation for 'x86_64-linux'... | The following derivations will be built:    /gnu/store/n3bclgnpk15cg1ldsv06yk6ad6p8wnqj-profile.drv    /gnu/store/xvfzdgdm1633m2yj5p66yzm9jjd3inzp-config.scm.drv ... ... New in this revision:   9 new packages: emacs-clang-format, emacs-gtk-look, fstrcmp,     python-pyelftools, r-aggregation, r-destiny, r-h5, r-savr, xmlrpc-c   14 packages upgraded: crossguid@0.0-2.fef89a4,     guile-newt@0-1.4eaa3cf84, java-ngs@2.9.3, kodi@18.0b5, ncbi-vdb@2.9.3,     ngs-sdk@2.9.3, python-ilinkedlist@0.3.1, r-minimal@3.5.1, r@3.5.1,     rmath-standalone@3.5.1, sra-tools@2.9.3, tadbit@0.2.0, vsearch@2.9.1,     wxmaxima@18.10.1 # guix describe Generation 29    Nov 09 2018 20:08:09    (current)   guix a961ae4     repository URL: https://git.savannah.gnu.org/git/guix.git     branch: master     commit: a961ae469cf81797df34f22eef0f0f5ca1a21e07 9. Nov 2018 19:39 by ludo@gnu.org : > Hello! > > <> znavko@tutanota.com > > skribis: > >> I watch an issue. Trying to roll-back and choose another kernel in grub I have no changes. Guix says 'Wrong type to upply: #t' > > This has been fixed a couple of days ago in commit > ea68b3f6527cf4a02c554cf3f6f446e30f4940f6. > > (Note that ‘guix pull’ was successful, despite the backtrace.) > > Sorry for the mess! > > Ludo’.