diff --git a/spacy/tests/regression/test_issue1727.py b/spacy/tests/regression/test_issue1727.py
new file mode 100644
index 000000000..f40b90c45
--- /dev/null
+++ b/spacy/tests/regression/test_issue1727.py
@@ -0,0 +1,23 @@
+from __future__ import unicode_literals
+import numpy
+from ...pipeline import Tagger
+from ...vectors import Vectors
+from ...vocab import Vocab
+from ..util import make_tempdir
+
+
+def test_issue1727():
+    data = numpy.ones((3, 300), dtype='f')
+    keys = [u'I', u'am', u'Matt']
+    vectors = Vectors(data=data, keys=keys)
+    tagger = Tagger(Vocab())
+    tagger.add_label('PRP')
+    tagger.begin_training()
+
+    assert tagger.cfg.get('pretrained_dims', 0) == 0
+    tagger.vocab.vectors = vectors
+
+    with make_tempdir() as path:
+        tagger.to_disk(path)
+        tagger = Tagger(Vocab()).from_disk(path)
+        assert tagger.cfg.get('pretrained_dims', 0) == 0