diff --git a/gnu/packages/admin.scm b/gnu/packages/admin.scm
index 51b40c8..84f86c5 100644
--- a/gnu/packages/admin.scm
+++ b/gnu/packages/admin.scm
@@ -201,7 +201,13 @@ client and server, a telnet client and server, and an rsh client and server.")
                       (delete-file (string-append bin "/groups"))
                       (for-each delete-file (find-files man "^groups\\."))
                       #t))
-                  %standard-phases))))
+                  (alist-cons-after
+                   'unpack
+                   (lambda _
+                     (for-each (lambda (file)
+                                 (utime file 0 0 0))
+                               (find-files "." "")))
+                   %standard-phases)))))
 
     (inputs (if (string-suffix? "-linux"
                                 (or (%current-target-system)