diff --git a/morituri/common/checksum.py b/morituri/common/checksum.py
index b027be5..9a943e1 100644
--- a/morituri/common/checksum.py
+++ b/morituri/common/checksum.py
@@ -163,8 +163,11 @@ class ChecksumTask(log.Loggable, gstreamer.GstPipelineTask):
             self.debug("checksum: %08X", self._checksum)
             self.debug("bytes: %d", self._bytes)
             if self._frameEnd != last:
-                print 'ERROR: did not get all frames, %d of %d missing' % (
+                msg = 'did not get all frames, %d of %d missing' % (
                     self._frameEnd - last, self._frameEnd)
+                self.warning(msg)
+                self.setException(common.MissingFrames(msg))
+                return
 
         self.checksum = self._checksum
 
diff --git a/morituri/common/common.py b/morituri/common/common.py
index 7245179..6b6ff65 100644
--- a/morituri/common/common.py
+++ b/morituri/common/common.py
@@ -170,6 +170,12 @@ class MissingDependencyException(Exception):
 class EmptyError(Exception):
     pass
 
+class MissingFrames(Exception):
+    """
+    Less frames decoded than expected.
+    """
+    pass
+
 
 def shrinkPath(path):
     """