diff --git a/changelog.d/19876.misc b/changelog.d/19876.misc
new file mode 100644
index 00000000000..694b5ddddee
--- /dev/null
+++ b/changelog.d/19876.misc
@@ -0,0 +1 @@
+Prevent an obtuse error masking a more user-friendly error when trying to run Synapse with an outdated rust module in certain cases.
\ No newline at end of file
diff --git a/synapse/util/__init__.py b/synapse/util/__init__.py
index 977a662d7a5..6b059c6b0e1 100644
--- a/synapse/util/__init__.py
+++ b/synapse/util/__init__.py
@@ -38,10 +38,8 @@
 from twisted.internet import defer
 from twisted.python.failure import Failure
 
-from synapse.types import JsonDict
-
 if typing.TYPE_CHECKING:
-    pass
+    from synapse.types import JsonDict
 
 logger = logging.getLogger(__name__)
 
@@ -189,7 +187,7 @@ def split_dict_to_fit_to_size(
     *,
     soft_max_size: int,
     wrapping_object_size: int = 2,
-) -> Iterator[tuple[dict[str, JsonDict], int]]:
+) -> Iterator[tuple[dict[str, "JsonDict"], int]]:
     """Splits a dict up into a list of dicts, each of which is small enough to
     fit into the given size when encoded as JSON. Every entry in the original
     dict is in exactly one of the resulting dicts.