diff --git a/java/src/org/broadinstitute/sting/utils/exceptions/UserException.java b/java/src/org/broadinstitute/sting/utils/exceptions/UserException.java
index f0dc3eeb3..2b21fc473 100755
--- a/java/src/org/broadinstitute/sting/utils/exceptions/UserException.java
+++ b/java/src/org/broadinstitute/sting/utils/exceptions/UserException.java
@@ -137,7 +137,7 @@ public class UserException extends ReviewedStingException {
 
     public static class MalformedBAM extends UserException {
         public MalformedBAM(SAMRecord read, String message) {
-            super(String.format("SAM/BAM file %s is malformed: %s", read.getFileSource().getReader(), message));
+            super(String.format("SAM/BAM file %s is malformed: %s", read.getFileSource() != null ? read.getFileSource().getReader() : "(none)", message));
         }
     }