diff --git a/lib/Slic3r/GUI.pm b/lib/Slic3r/GUI.pm
index fd46cc5ebb..00e56f4faa 100644
--- a/lib/Slic3r/GUI.pm
+++ b/lib/Slic3r/GUI.pm
@@ -253,6 +253,7 @@ sub warning_catcher {
     my ($self, $message_dialog) = @_;
     return sub {
         my $message = shift;
+        return if $message =~ /GLUquadricObjPtr|Attempt to free unreferenced scalar/;
         my @params = ($message, 'Warning', wxOK | wxICON_WARNING);
         $message_dialog
             ? $message_dialog->(@params)
diff --git a/lib/Slic3r/GUI/Plater.pm b/lib/Slic3r/GUI/Plater.pm
index 286a524e2e..dc17bdcf89 100644
--- a/lib/Slic3r/GUI/Plater.pm
+++ b/lib/Slic3r/GUI/Plater.pm
@@ -159,6 +159,7 @@ sub new {
     EVT_COMMAND($self, -1, $THUMBNAIL_DONE_EVENT, sub {
         my ($self, $event) = @_;
         my ($obj_idx, $thumbnail) = @{$event->GetData};
+        return if !$self->{objects}[$obj_idx];  # object was deleted before thumbnail generation completed
         $self->{objects}[$obj_idx]->thumbnail($thumbnail->clone);
         $self->on_thumbnail_made($obj_idx);
     });