diff --git a/public/java/src/org/broadinstitute/sting/gatk/io/storage/VariantContextWriterStorage.java b/public/java/src/org/broadinstitute/sting/gatk/io/storage/VariantContextWriterStorage.java
index c6438cfdb..31f6d5954 100644
--- a/public/java/src/org/broadinstitute/sting/gatk/io/storage/VariantContextWriterStorage.java
+++ b/public/java/src/org/broadinstitute/sting/gatk/io/storage/VariantContextWriterStorage.java
@@ -186,7 +186,7 @@ public class VariantContextWriterStorage implements Storage<VariantContextWriter
             // that way we don't assume it's a specific type
             final FeatureManager.FeatureDescriptor fd = new FeatureManager().getByFiletype(file);
             if ( fd == null )
-                throw new ReviewedStingException("Unexpectedly couldn't find valid codec for temporary output file " + file);
+                throw new UserException.LocalParallelizationProblem(file);
 
             final FeatureCodec<VariantContext> codec = fd.getCodec();
             final AbstractFeatureReader<VariantContext> source =
diff --git a/public/java/src/org/broadinstitute/sting/utils/exceptions/UserException.java b/public/java/src/org/broadinstitute/sting/utils/exceptions/UserException.java
index faafc611a..eaa8d7943 100755
--- a/public/java/src/org/broadinstitute/sting/utils/exceptions/UserException.java
+++ b/public/java/src/org/broadinstitute/sting/utils/exceptions/UserException.java
@@ -129,6 +129,12 @@ public class UserException extends ReviewedStingException {
         }
     }
 
+    public static class LocalParallelizationProblem extends UserException {
+        public LocalParallelizationProblem(final File file) {
+            super(String.format("There was a failure because temporary file %s could not be found while running the GATK with more than one thread.  Possible causes for this problem include: your system's open file handle limit is too small, your output or temp directories do not have sufficient space, or just an isolated file system blip", file.getAbsolutePath()));
+        }
+    }
+
     public static class NotEnoughMemory extends UserException {
         public NotEnoughMemory() {
             super(String.format("There was a failure because you did not provide enough memory to run this program.  See the -Xmx JVM argument to adjust the maximum heap size provided to Java"));