diff --git a/src/engine/playback.cpp b/src/engine/playback.cpp
index 50f2dde44..ecd502f11 100644
--- a/src/engine/playback.cpp
+++ b/src/engine/playback.cpp
@@ -1685,7 +1685,10 @@ void DivEngine::nextBuf(float** in, float** out, int inChans, int outChans, unsi
   totalProcessed=size-(runLeftG>>MASTER_CLOCK_PREC);
 
   for (int i=0; i<song.systemLen; i++) {
-    if (size>disCont[i].lastAvail) continue;
+    if (size>disCont[i].lastAvail) {
+      logW("%d: size>lastAvail! %d>%d",i,size,disCont[i].lastAvail);
+      continue;
+    }
     disCont[i].fillBuf(disCont[i].runtotal,disCont[i].lastAvail,size-disCont[i].lastAvail);
   }