diff --git a/gui/action.cpp b/gui/action.cpp
index 37534fa..b51e8aa 100755
--- a/gui/action.cpp
+++ b/gui/action.cpp
@@ -1983,7 +1983,8 @@
 {
 	operation_start("Set Boot Slot");
 	if (!simulate) {
-		PartitionManager.UnMount_By_Path("/vendor",true);
+		if (PartitionManager.Find_Partition_By_Path("/vendor"))
+			PartitionManager.UnMount_By_Path("/vendor",true);
 		PartitionManager.Set_Active_Slot(arg);
 	} else
 		simulate_progress_bar();