diff -up shadow-4.6/libmisc/find_new_gid.c.min-limit shadow-4.6/libmisc/find_new_gid.c
--- shadow-4.6/libmisc/find_new_gid.c.min-limit	2018-04-29 18:42:37.000000001 +0200
+++ shadow-4.6/libmisc/find_new_gid.c	2018-11-06 10:07:14.567611067 +0100
@@ -81,6 +81,12 @@ static int get_ranges (bool sys_group, g
                             getdef_ulong ("GID_MIN", 1000UL),
                             (unsigned long) *max_id);
 			return EINVAL;
+		/*
+		 * Zero is reserved for root and the allocation algorithm does not
+		 * work right with it.
+		 */
+		if (*min_id == 0) {
+			*min_id = (gid_t) 1;
 		}
 	} else {
 		/* Non-system groups */
diff -up shadow-4.6/libmisc/find_new_uid.c.min-limit shadow-4.6/libmisc/find_new_uid.c
--- shadow-4.6/libmisc/find_new_uid.c.min-limit	2018-04-29 18:42:37.000000001 +0200
+++ shadow-4.6/libmisc/find_new_uid.c	2018-11-06 10:07:34.392075491 +0100
@@ -81,6 +81,12 @@ static int get_ranges (bool sys_user, ui
                             getdef_ulong ("UID_MIN", 1000UL),
                             (unsigned long) *max_id);
 			return EINVAL;
+		/*
+		 * Zero is reserved for root and the allocation algorithm does not
+		 * work right with it.
+		 */
+		if (*min_id == 0) {
+			*min_id = (uid_t) 1;
 		}
 	} else {
 		/* Non-system users */