diff --git a/src/slic3r/GUI/RemovableDriveManagerMM.mm b/src/slic3r/GUI/RemovableDriveManagerMM.mm
index 45bd21bcf..3bb017a3a 100644
--- a/src/slic3r/GUI/RemovableDriveManagerMM.mm
+++ b/src/slic3r/GUI/RemovableDriveManagerMM.mm
@@ -23,6 +23,7 @@
 {
     NSLog(@"add unmount observer");
     [[[NSWorkspace sharedWorkspace] notificationCenter] addObserver:self selector: @selector(on_device_unmount:) name:NSWorkspaceDidUnmountNotification object:nil];
+    [[[NSWorkspace sharedWorkspace] notificationCenter] addObserver:self selector: @selector(on_device_unmount:) name:NSWorkspaceDidMountNotification object:nil];
 }
 -(NSArray*) list_dev
 {