diff --git a/cpp/Enums.h b/cpp/Enums.h
index 735d6dd6..95d11b74 100644
--- a/cpp/Enums.h
+++ b/cpp/Enums.h
@@ -22,3 +22,29 @@ enum class StorageDataType : unsigned char {
   // allowing representation of values from 2e-9 to 448.
   E4M3 = 3 << 4,
 };
+
+inline const std::string toString(StorageDataType sdt) {
+  switch (sdt) {
+  case StorageDataType::Float8:
+    return "Float8";
+  case StorageDataType::Float32:
+    return "Float32";
+  case StorageDataType::E4M3:
+    return "E4M3";
+  default:
+    return "Unknown storage data type (value " + std::to_string((int)sdt) + ")";
+  }
+}
+
+inline const std::string toString(SpaceType space) {
+  switch (space) {
+  case SpaceType::Euclidean:
+    return "Euclidean";
+  case SpaceType::Cosine:
+    return "Cosine";
+  case SpaceType::InnerProduct:
+    return "InnerProduct";
+  default:
+    return "Unknown space type (value " + std::to_string((int)space) + ")";
+  }
+}
\ No newline at end of file
diff --git a/cpp/TypedIndex.h b/cpp/TypedIndex.h
index 719bacd7..510d7288 100644
--- a/cpp/TypedIndex.h
+++ b/cpp/TypedIndex.h
@@ -29,6 +29,7 @@
 #include <ratio>
 
 #include "E4M3.h"
+#include "Enums.h"
 #include "Index.h"
 #include "Metadata.h"
 #include "array_utils.h"
diff --git a/java/com_spotify_voyager_jni_Index.cpp b/java/com_spotify_voyager_jni_Index.cpp
index 029ca6f0..dcbae44d 100644
--- a/java/com_spotify_voyager_jni_Index.cpp
+++ b/java/com_spotify_voyager_jni_Index.cpp
@@ -21,6 +21,7 @@
 #include "com_spotify_voyager_jni_Index.h"
 #include "JavaInputStream.h"
 #include "JavaOutputStream.h"
+#include <Enums.h>
 #include <Index.h>
 #include <TypedIndex.h>
 
@@ -709,16 +710,23 @@ void Java_com_spotify_voyager_jni_Index_nativeLoadFromFileWithParameters(
     if (metadata) {
       if (metadata->getStorageDataType() !=
           toStorageDataType(env, storageDataType)) {
-        throw std::domain_error("Provided storage data type does not match "
-                                "the data type used in this file.");
+        throw std::domain_error(
+            "Provided storage data type (" +
+            toString(toStorageDataType(env, storageDataType)) +
+            ") does not match the data type used in this file (" +
+            toString(metadata->getStorageDataType()) + ").");
       }
       if (metadata->getSpaceType() != toSpaceType(env, spaceType)) {
-        throw std::domain_error("Provided space type does not match "
-                                "the space type used in this file.");
+        throw std::domain_error(
+            "Provided space type (" + toString(toSpaceType(env, spaceType)) +
+            ") does not match the space type used in this file (" +
+            toString(metadata->getSpaceType()) + ").");
       }
       if (metadata->getNumDimensions() != numDimensions) {
-        throw std::domain_error("Provided number of dimensions does not match "
-                                "the number of dimensions used in this file.");
+        throw std::domain_error(
+            "Provided number of dimensions (" + std::to_string(numDimensions) +
+            ") does not match the number of dimensions used in this file (" +
+            std::to_string(metadata->getNumDimensions()) + ").");
       }
     }
 
@@ -760,16 +768,23 @@ void Java_com_spotify_voyager_jni_Index_nativeLoadFromInputStreamWithParameters(
     if (metadata) {
       if (metadata->getStorageDataType() !=
           toStorageDataType(env, storageDataType)) {
-        throw std::domain_error("Provided storage data type does not match "
-                                "the data type used in this file.");
+        throw std::domain_error(
+            "Provided storage data type (" +
+            toString(toStorageDataType(env, storageDataType)) +
+            ") does not match the data type used in this file (" +
+            toString(metadata->getStorageDataType()) + ").");
       }
       if (metadata->getSpaceType() != toSpaceType(env, spaceType)) {
-        throw std::domain_error("Provided space type does not match "
-                                "the space type used in this file.");
+        throw std::domain_error(
+            "Provided space type (" + toString(toSpaceType(env, spaceType)) +
+            ") does not match the space type used in this file (" +
+            toString(metadata->getSpaceType()) + ").");
       }
       if (metadata->getNumDimensions() != numDimensions) {
-        throw std::domain_error("Provided number of dimensions does not match "
-                                "the number of dimensions used in this file.");
+        throw std::domain_error(
+            "Provided number of dimensions (" + std::to_string(numDimensions) +
+            ") does not match the number of dimensions used in this file (" +
+            std::to_string(metadata->getNumDimensions()) + ").");
       }
     }
 
diff --git a/python/bindings.cpp b/python/bindings.cpp
index 17d89c4c..fb5d68ad 100644
--- a/python/bindings.cpp
+++ b/python/bindings.cpp
@@ -911,17 +911,24 @@ binary data (i.e.: ``open(..., \"rb\")`` or ``io.BinaryIO``, etc.).
 
         if (metadata) {
           if (metadata->getStorageDataType() != storageDataType) {
-            throw std::domain_error("Provided storage data type does not match "
-                                    "the data type used in this file.");
+            throw std::domain_error(
+                "Provided storage data type (" + toString(storageDataType) +
+                ") does not match the data type used in this file (" +
+                toString(metadata->getStorageDataType()) + ").");
           }
           if (metadata->getSpaceType() != space) {
-            throw std::domain_error("Provided space type does not match "
-                                    "the space type used in this file.");
+            throw std::domain_error(
+                "Provided space type (" + toString(space) +
+                ") does not match the space type used in this file (" +
+                toString(metadata->getSpaceType()) + ").");
           }
           if (metadata->getNumDimensions() != num_dimensions) {
             throw std::domain_error(
-                "Provided number of dimensions does not match "
-                "the number of dimensions used in this file.");
+                "Provided number of dimensions (" +
+                std::to_string(num_dimensions) +
+                ") does not match the number of dimensions used in this file "
+                "(" +
+                std::to_string(metadata->getNumDimensions()) + ").");
           }
         }
 
@@ -973,17 +980,24 @@ binary data (i.e.: ``open(..., \"rb\")`` or ``io.BinaryIO``, etc.).
 
         if (metadata) {
           if (metadata->getStorageDataType() != storageDataType) {
-            throw std::domain_error("Provided storage data type does not match "
-                                    "the data type used in this file.");
+            throw std::domain_error(
+                "Provided storage data type (" + toString(storageDataType) +
+                ") does not match the data type used in this file (" +
+                toString(metadata->getStorageDataType()) + ").");
           }
           if (metadata->getSpaceType() != space) {
-            throw std::domain_error("Provided space type does not match "
-                                    "the space type used in this file.");
+            throw std::domain_error(
+                "Provided space type (" + toString(space) +
+                ") does not match the space type used in this file (" +
+                toString(metadata->getSpaceType()) + ").");
           }
           if (metadata->getNumDimensions() != num_dimensions) {
             throw std::domain_error(
-                "Provided number of dimensions does not match "
-                "the number of dimensions used in this file.");
+                "Provided number of dimensions (" +
+                std::to_string(num_dimensions) +
+                ") does not match the number of dimensions used in this file "
+                "(" +
+                std::to_string(metadata->getNumDimensions()) + ").");
           }
         }
 
diff --git a/python/tests/test_load_indices.py b/python/tests/test_load_indices.py
index e9516a70..3c17701e 100644
--- a/python/tests/test_load_indices.py
+++ b/python/tests/test_load_indices.py
@@ -112,6 +112,35 @@ def test_load_v1_indices(load_from_stream: bool, index_filename: str):
         np.testing.assert_allclose(index[_id], expected_vector, atol=0.2)
 
 
+@pytest.mark.parametrize("load_from_stream", [False, True])
+@pytest.mark.parametrize("index_filename", glob(os.path.join(INDEX_FIXTURE_DIR, "v1", "*.hnsw")))
+def test_v1_indices_must_have_no_parameters_or_must_match(
+    load_from_stream: bool, index_filename: str
+):
+    space = detect_space_from_filename(index_filename)
+    num_dimensions = detect_num_dimensions_from_filename(index_filename)
+    storage_data_type = detect_storage_datatype_from_filename(index_filename)
+    with pytest.raises(ValueError) as exception:
+        if load_from_stream:
+            with open(index_filename, "rb") as f:
+                Index.load(
+                    f,
+                    space=space,
+                    num_dimensions=num_dimensions + 1,
+                    storage_data_type=storage_data_type,
+                )
+        else:
+            Index.load(
+                index_filename,
+                space=space,
+                num_dimensions=num_dimensions + 1,
+                storage_data_type=storage_data_type,
+            )
+    assert "number of dimensions" in repr(exception)
+    assert f"({num_dimensions})" in repr(exception)
+    assert f"({num_dimensions + 1})" in repr(exception)
+
+
 @pytest.mark.parametrize(
     "data,should_pass",
     [