diff --git a/src/effects/nyquist/Nyquist.cpp b/src/effects/nyquist/Nyquist.cpp
index 65bca0b61e25c867b77ef78f376104ee63b5e512..0112488f1b874c69ee2a526882e3b57deb0f460c 100644
--- a/src/effects/nyquist/Nyquist.cpp
+++ b/src/effects/nyquist/Nyquist.cpp
@@ -937,8 +937,11 @@ bool NyquistEffect::Process(EffectInstance &, EffectSettings &settings)
       auto &mCurLen = nyxContext.mCurLen;
 
       mCurChannelGroup = pRange ? *pRange->first : nullptr;
-      mCurTrack[0] = (*mCurChannelGroup->Channels().begin()).get();
+      mCurTrack[0] = mCurChannelGroup
+         ? (*mCurChannelGroup->Channels().begin()).get()
+         : nullptr;
       mCurNumChannels = 1;
+      assert(mCurChannelGroup != nullptr || bOnePassTool);
       if ( (mT1 >= mT0) || bOnePassTool ) {
          if (bOnePassTool) {
          }