I bumped into this issue yesterday and thanks to the comments here I was able to run fsck in the end.

As an inexperienced guix user, I would like to add some details which I believe could be useful to someone else :

I had forgotten I was updating packages and accidentally closed my laptop, which closed my session. Reopening the session, my computer was frozen (mouse and keyboard not responding within several minutes). After manual reboot, I get the following error : /dev/XXX: UNEXPECTED INCONSISTENCY; RUN fsck MANUALLY.

Within the command prompt bourne@(guile-user) I try fsck.

However, fsck command was not recognized. Eventually, my solution was :

• check the name of the e2fsck folder (in my case it ended with e2fsc k-static-1.47.0) :
  cd /gnu/store
  ls
  
• switch to scheme language :
  ,language scheme
• Copy Mark's solution after adapting to my folder's name :
  
  (use-modules (ice-9 ftw) (srfi srfi-26))
  (define dirs (scandir "/gnu/store" (cut string-suffix? "e2fsck-static-1.47.0" <>)))
  (define e2fsck (string-append "/gnu/store/" (car dirs) "/sbin/e2fsck"))
  (system* e2fsck "/dev/XXX")

The command (system* fsck.ext4 "/dev/XXX") did not work for me because fsck.ext4 was not found.

A question : perhaps the easiest solution (which I only think of right now) was :

e2fsck "/dev/XXX"

Thanks,

Vilgour