--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -233,6 +233,16 @@ The @code{guix-daemon} program may then be run as @code{root} with:
 # guix-daemon --build-users-group=guix-builder
 @end example
 
+In such a multi-user setup, @dfn{user profiles}---i.e., the set of
+user-installed packages as seen by @command{guix-package}
+(@pxref{Invoking guix-package})---must be stored in a place registered
+as a @dfn{garbage-collector root}.  That directory is normally
+@code{@var{localstatedir}/profiles/per-user/@var{user}}, where
+@var{localstatedir} is the value passed to @code{configure} as
+@code{--localstatedir}, and @var{user} is the user name.  This directory
+must be created by @code{root}, with @var{user} as the owner.  When it
+does not exist, @command{guix-package} emits an error about it.
+
 Guix may also be used in a single-user setup, with @command{guix-daemon}
 running as a unprivileged user.  However, to maximize non-interference
 of build processes, the daemon still needs to perform certain operations
diff --git a/guix-package.in b/guix-package.in
index 450d09e..ec09cc4 100644
--- a/guix-package.in
+++ b/guix-package.in
@@ -36,6 +36,7 @@ exec ${GUILE-@GUILE@} -L "@guilemoduledir@" -l "$0"    \
   #:use-module (guix packages)
   #:use-module (guix utils)
   #:use-module (guix config)
+  #:use-module ((guix build utils) #:select (directory-exists?))
   #:use-module (ice-9 ftw)
   #:use-module (ice-9 format)
   #:use-module (ice-9 match)
@@ -465,6 +466,25 @@ Install, remove, or upgrade PACKAGES in a single transaction.\n"))
                (not (file-exists? %user-environment-directory)))
       (symlink %current-profile %user-environment-directory))
 
+    ;; Attempt to create /…/profiles/per-user/$USER if needed.
+    (unless (or (not (equal? (assoc-ref opts 'profile) %current-profile))
+                (directory-exists? %profile-directory))
+      (catch 'system-error
+        (lambda ()
+          (mkdir %profile-directory))
+        (lambda args
+          ;; Often, we cannot create %PROFILE-DIRECTORY because its
+          ;; parent directory is root-owned and we're running
+          ;; unprivileged.
+          (format (current-error-port)
+                  (_ "error: while creating directory `~a': ~a~%")
+                  %profile-directory
+                  (strerror (system-error-errno args)))
+          (format (current-error-port)
+                  (_ "Please create the `~a' directory, with you as the owner.~%")
+                  %profile-directory)
+          (exit 1))))
+
     (with-error-handling
       (or (process-query opts)
           (parameterize ((%guile-for-build