diff --git a/utils.c b/utils.c
index 220c7d87..52791b53 100644
--- a/utils.c
+++ b/utils.c
@@ -798,40 +798,52 @@ err_nomem:
 	return -ENOMEM;
 }
 
-static void btrfs_wipe_existing_sb(int fd)
+static int btrfs_wipe_existing_sb(int fd)
 {
 	const char *off = NULL;
 	size_t len = 0;
 	loff_t offset;
 	char buf[BUFSIZ];
-	int rc = 0;
+	int ret = 0;
 	blkid_probe pr = NULL;
 
 	pr = blkid_new_probe();
 	if (!pr)
-		return;
+		return -1;
 
-	if (blkid_probe_set_device(pr, fd, 0, 0))
+	if (blkid_probe_set_device(pr, fd, 0, 0)) {
+		ret = -1;
 		goto out;
+	}
 
-	rc = blkid_probe_lookup_value(pr, "SBMAGIC_OFFSET", &off, NULL);
-	if (!rc)
-		rc = blkid_probe_lookup_value(pr, "SBMAGIC", NULL, &len);
+	ret = blkid_probe_lookup_value(pr, "SBMAGIC_OFFSET", &off, NULL);
+	if (!ret)
+		ret = blkid_probe_lookup_value(pr, "SBMAGIC", NULL, &len);
 
-	if (rc || len == 0 || off == NULL)
+	if (ret || len == 0 || off == NULL) {
+		/*
+		 * If lookup fails, the probe did not find any values, eg. for
+		 * a file image or a loop device. Soft error.
+		 */
+		ret = 1;
 		goto out;
+	}
 
 	offset = strtoll(off, NULL, 10);
 	if (len > sizeof(buf))
 		len = sizeof(buf);
 
 	memset(buf, 0, len);
-	rc = pwrite(fd, buf, len, offset);
+	ret = pwrite(fd, buf, len, offset);
+	if (ret != len) {
+		fprintf(stderr, "ERROR: cannot wipe existing superblock\n");
+		ret = -1;
+	}
 	fsync(fd);
 
 out:
 	blkid_free_probe(pr);
-	return;
+	return ret;
 }
 
 int btrfs_prepare_device(int fd, char *file, int zero_end, u64 *block_count_ret,
@@ -885,7 +897,12 @@ int btrfs_prepare_device(int fd, char *file, int zero_end, u64 *block_count_ret,
 		return 1;
 	}
 
-	btrfs_wipe_existing_sb(fd);
+	ret = btrfs_wipe_existing_sb(fd);
+	if (ret < 0) {
+		fprintf(stderr, "ERROR: cannot wipe superblocks on '%s'\n",
+				file);
+		return 1;
+	}
 
 	*block_count_ret = block_count;
 	return 0;