diff -Nur cron-3.0pl1.orig/cron.c cron-3.0pl1/cron.c
--- cron-3.0pl1.orig/cron.c	2022-06-25 20:59:38.000000000 +0100
+++ cron-3.0pl1/cron.c	2022-06-25 21:09:11.707716332 +0100
@@ -147,7 +147,9 @@
 	database.sys_mtime = (time_t) 0;
 	database.user_mtime = (time_t) 0;
 	database.sysd_mtime = (time_t) 0;
-	load_database(&database);
+	/* 1 here = always load database, regardless of
+	 * mtime */
+	load_database(&database, 1);
 	set_time(TRUE);
 	run_reboot_jobs(&database);
 	timeRunning = virtualTime = clockTime;
@@ -174,7 +176,7 @@
 		timeRunning = clockTime;
 
 		check_orphans(&database);
-		load_database(&database);
+		load_database(&database, 0);
 
 		/*
 		 * ... calculate how the current time differs from
diff -Nur cron-3.0pl1.orig/cron.h cron-3.0pl1/cron.h
--- cron-3.0pl1.orig/cron.h	2022-06-25 20:59:38.000000000 +0100
+++ cron-3.0pl1/cron.h	2022-06-25 21:02:39.659707221 +0100
@@ -225,7 +225,7 @@
 
 void		set_cron_uid __P((void)),
 		set_cron_cwd __P((void)),
-		load_database __P((cron_db *)),
+		load_database __P((cron_db *, int)),
 		open_logfile __P((void)),
 		sigpipe_func __P((void)),
 		job_add __P((entry *, user *)),
diff -Nur cron-3.0pl1.orig/database.c cron-3.0pl1/database.c
--- cron-3.0pl1.orig/database.c	2022-06-25 20:59:38.000000000 +0100
+++ cron-3.0pl1/database.c	2022-06-25 21:07:11.183713531 +0100
@@ -57,8 +57,9 @@
 static void free_orphan(orphan *o);
 
 void
-load_database(old_db)
+load_database(old_db, always_load)
 	cron_db		*old_db;
+	int		always_load;
 {
 	DIR		*dir;
 	struct stat	statbuf;
@@ -105,7 +106,7 @@
 	 * we avoid reading of SYSCRONDIR and don't change its access time.
 	 * This is especially important on laptops with APM.
 	 */
-	if (old_db->sysd_mtime != syscrond_stat.st_mtime) {
+	if (old_db->sysd_mtime != syscrond_stat.st_mtime || always_load) {
 		syscrond_change = 1;
 	} else {
 	        /* Look through the individual files */
@@ -138,13 +139,15 @@
 	/* if spooldir's mtime has not changed, we don't need to fiddle with
 	 * the database.
 	 *
-	 * Note that old_db->mtime is initialized to 0 in main(), and
-	 * so is guaranteed to be different than the stat() mtime the first
-	 * time this function is called.
+	 * we used to rely on old_db->mtime being 0 when first run to force
+	 * a database load here, but this breaks if the actual mtime of our
+	 * crontab files / directories is 0, e.g. on an ostree checkout. See
+	 * https://bugs.launchpad.net/ubuntu/+source/cron/+bug/1773229
 	 */
 	if ((old_db->user_mtime == statbuf.st_mtime) &&
 		(old_db->sys_mtime == syscron_stat.st_mtime) &&
-		(!syscrond_change)) {
+		(!syscrond_change) &&
+		(!always_load)) {
 		Debug(DLOAD, ("[%d] spool dir mtime unch, no load needed.\n",
 			      getpid()))
 		return;