diff --git a/main b/main
index 6954eb3..828f799 100755
Binary files a/main and b/main differ
diff --git a/main.c b/main.c
index 6e21385..d44cff4 100644
--- a/main.c
+++ b/main.c
@@ -109,6 +109,7 @@ struct MsgPort *timerPort;
 
 APTR bellSound = NULL;
 struct Library *DataTypesBase;
+BYTE waitForSoundSignalNumber;
 
 // our business logic
 // for how long should I cook this pizza?
@@ -182,6 +183,8 @@ int setup(void) {
   if (NULL == (DataTypesBase = OpenLibrary("datatypes.library", 40))) {
     // this is ok, we just won't play sound
     printf("no sound!");
+  } else {
+    waitForSoundSignalNumber = AllocSignal(-1);
   }
 
   return 1;
@@ -194,6 +197,7 @@ void teardown(void) {
   // http://amigadev.elowar.com/read/ADCD_2.1/Devices_Manual_guide/node0196.html
   if (DataTypesBase) {
     CloseLibrary(DataTypesBase);
+    FreeSignal(waitForSoundSignalNumber);
   }
   if (TimerIO) {
     CloseDevice((struct IORequest *)TimerIO);
@@ -708,7 +712,6 @@ void handleIntuitionMessage(struct IntuiMessage *iMessage) {
   }
 }
 
-BYTE waitForSoundSignalNumber;
 
 /**
  * Start playing a bell sound, then wait for it to finish.
@@ -717,8 +720,8 @@ void startBellSound(void) {
   struct dtTrigger myTrigger;
   ULONG soundPlayResult;
 
+  if (!DataTypesBase) return;
   // https://amigaworld.net/modules/newbb/viewtopic.php?forum=15&topic_id=39094&post_id=735120&viewmode=thread&order=0#735120
- waitForSoundSignalNumber = AllocSignal(-1);
 
   if (bellSound = NewDTObject(
         BELL_FILENAME,