diff --git a/lib/activate/activate.c b/lib/activate/activate.c
index 8605e5293..14adc7320 100644
--- a/lib/activate/activate.c
+++ b/lib/activate/activate.c
@@ -2193,16 +2193,23 @@ static int _lv_suspend(struct cmd_context *cmd, const char *lvid_s,
 		/* FIXME Consider aborting here */
 		stack;
 
-	if (!laopts->origin_only &&
-	    (lv_is_origin(lv_pre) || lv_is_cow(lv_pre)))
-		lockfs = 1;
-
-	/* Converting non-thin LV to thin external origin ? */
-	if (!lv_is_thin_volume(lv) && lv_is_thin_volume(lv_pre))
-		lockfs = 1; /* Sync before conversion */
-
+	/* Require fs synchronization when taking a thin snapshot */
 	if (laopts->origin_only && lv_is_thin_volume(lv) && lv_is_thin_volume(lv_pre))
 		lockfs = 1;
+	/* Require fs synchronization when taking a thick snapshot */
+	else if (!laopts->origin_only &&
+		 (lv_is_origin(lv_pre) || lv_is_cow(lv_pre)))
+		lockfs = 1;
+	/* Require fs synchronization when converting a non-thin LV to a thin LV or
+	 * a non/thin LV with/out external origin to a thin LV with external origin LV. */
+	else if (!laopts->origin_only &&
+		 lv_is_thin_volume(lv_pre) &&		/* new LV is a Thin */
+		 (!lv_is_thin_volume(lv) ||		/* and either the existing LV is NOT a Thin */
+		  (first_seg(lv_pre)->external_lv &&	/* or the existing LV IS Thin and the new LV is Thin with the external origin */
+		   (!first_seg(lv)->external_lv ||	/* and check if existing Thin is either without the external origin */
+		    memcmp(&first_seg(lv_pre)->external_lv->lvid.id[1], /* or it uses a different external origin */
+			   &first_seg(lv)->external_lv->lvid.id[1], ID_LEN) != 0))))
+		lockfs = 1;
 
 	if (!lv_is_locked(lv) && lv_is_locked(lv_pre) &&
 	    (pvmove_lv = find_pvmove_lv_in_lv(lv_pre))) {