diff --git a/lib/Slic3r.pm b/lib/Slic3r.pm
index 37f242e72..d759d1b34 100644
--- a/lib/Slic3r.pm
+++ b/lib/Slic3r.pm
@@ -103,11 +103,14 @@ sub spawn_thread {
     my $parent_tid = threads->tid;
     lock @threads;
     
+    # Set up a default handler for preventing crashes in case signals are received before
+    # thread sets its handlers.
+    $SIG{'STOP'} = sub {};
+    
     @_ = ();
     my $thread = threads->create(sub {
         @my_threads = ();
         
-        Slic3r::debugf "Starting thread %d (parent: %d)...\n", threads->tid, $parent_tid;
         local $SIG{'KILL'} = sub {
             Slic3r::debugf "Exiting thread %d...\n", threads->tid;
             $parallel_sema->up if $parallel_sema;
@@ -119,6 +122,7 @@ sub spawn_thread {
             $pause_sema->down;
             $pause_sema->up;
         };
+        Slic3r::debugf "Starting thread %d (parent: %d)...\n", threads->tid, $parent_tid;
         $cb->();
     });
     push @my_threads, $thread->tid;