diff --git a/lib/Slic3r/GUI/Plater.pm b/lib/Slic3r/GUI/Plater.pm
index 2fa2db774..c0c440284 100644
--- a/lib/Slic3r/GUI/Plater.pm
+++ b/lib/Slic3r/GUI/Plater.pm
@@ -523,6 +523,8 @@ sub on_export_completed {
     my $self = shift;
     my ($message) = @_;
     
+    $self->{export_thread} = undef;
+    $self->statusbar->SetCancelCallback(undef);
     $self->statusbar->StopBusy;
     $self->statusbar->SetStatusText("G-code file exported to $self->{output_file}");
     Wx::MessageDialog->new($self, $message, 'Done!', wxOK | wxICON_INFORMATION)->ShowModal;