diff --git a/machine/corpora/corpora_utils.py b/machine/corpora/corpora_utils.py
index 09437463..98e67c10 100644
--- a/machine/corpora/corpora_utils.py
+++ b/machine/corpora/corpora_utils.py
@@ -15,6 +15,14 @@
 T = TypeVar("T")
 
 
+def alignment_exception(refs: Iterable[str]) -> TypeError:
+    return TypeError(
+        f'Invalid format in {", ".join(refs)}. '
+        "Mismatched key formats. There may be an extraneous tab, "
+        "missing ref, or inconsistent use of user-defined refs."
+    )
+
+
 def batch(iterable: Iterable[T], batch_size: int) -> Iterable[Sequence[T]]:
     if isinstance(iterable, Sequence) and len(iterable) <= batch_size:
         yield iterable
diff --git a/machine/corpora/n_parallel_text_corpus.py b/machine/corpora/n_parallel_text_corpus.py
index c2098aae..cf3cac0d 100644
--- a/machine/corpora/n_parallel_text_corpus.py
+++ b/machine/corpora/n_parallel_text_corpus.py
@@ -2,6 +2,7 @@
 from typing import Any, Callable, Iterable, List, Optional, Sequence, Set, cast
 
 from ..scripture.verse_ref import Versification
+from .corpora_utils import alignment_exception
 from .n_parallel_text_corpus_base import NParallelTextCorpusBase
 from .n_parallel_text_row import NParallelTextRow
 from .scripture_ref import ScriptureRef
@@ -181,7 +182,10 @@ def _get_rows(self, generators: List[TextCorpusEnumerator]) -> Iterable[NParalle
                         refs.append(row.ref)
                     else:
                         refs.append(None)
-                min_ref_indexes = self._min_ref_indexes(refs)
+                try:
+                    min_ref_indexes = self._min_ref_indexes(refs)
+                except TypeError as e:
+                    raise alignment_exception([str(r.ref) for r in current_rows if r is not None]) from e
                 non_min_ref_indexes = list(set(range(0, self.n)).difference(min_ref_indexes))
                 if (
                     len(min_ref_indexes) < num_remaining_rows
@@ -274,6 +278,8 @@ def _get_rows(self, generators: List[TextCorpusEnumerator]) -> Iterable[NParalle
                         if is_completed:
                             num_completed += 1
                             num_remaining_rows -= 1
+                else:
+                    raise alignment_exception([str(current_rows[i].ref) for i in min_ref_indexes])
 
             if range_info.is_in_range:
                 yield range_info.create_row()
@@ -362,9 +368,12 @@ def _create_min_ref_rows(
                 yield row
 
     def _check_same_ref_rows(self, same_ref_rows: List[TextRow], other_row: TextRow) -> bool:
-        if len(same_ref_rows) > 0 and self.row_ref_comparer(same_ref_rows[0].ref, other_row.ref) != 0:
-            same_ref_rows.clear()
-        return len(same_ref_rows) > 0
+        try:
+            if len(same_ref_rows) > 0 and self.row_ref_comparer(same_ref_rows[0].ref, other_row.ref) != 0:
+                same_ref_rows.clear()
+            return len(same_ref_rows) > 0
+        except TypeError as e:
+            raise alignment_exception([str(same_ref_rows[0].ref), str(other_row.ref)]) from e
 
     def _create_same_ref_rows(
         self,
diff --git a/machine/corpora/standard_parallel_text_corpus.py b/machine/corpora/standard_parallel_text_corpus.py
index eac12954..7521e3f0 100644
--- a/machine/corpora/standard_parallel_text_corpus.py
+++ b/machine/corpora/standard_parallel_text_corpus.py
@@ -4,6 +4,7 @@
 from typing import Callable, Generator, Iterable, Optional
 
 from .alignment_corpus import AlignmentCorpus
+from .corpora_utils import alignment_exception
 from .dictionary_alignment_corpus import DictionaryAlignmentCorpus
 from .n_parallel_text_corpus import NParallelTextCorpus, default_row_ref_comparer
 from .parallel_text_corpus import ParallelTextCorpus
@@ -68,7 +69,10 @@ def _get_rows(self, text_ids: Optional[Iterable[str]]) -> Generator[ParallelText
                 if self._alignment_corpus is not None and all([len(n) > 0 for n in n_row.n_segments]):
                     while True:
                         if alignment_row is not None:
-                            compare_alignment_corpus = self._row_ref_comparer(n_row.ref, alignment_row.ref)
+                            try:
+                                compare_alignment_corpus = self._row_ref_comparer(n_row.ref, alignment_row.ref)
+                            except TypeError as e:
+                                raise alignment_exception([str(r) for r in n_row.n_refs]) from e
                         else:
                             compare_alignment_corpus = 1
                         if compare_alignment_corpus >= 0: