diff --git a/c/lib.cpp b/c/lib.cpp
index 14332d85..a35acaa6 100644
--- a/c/lib.cpp
+++ b/c/lib.cpp
@@ -119,7 +119,7 @@ USEARCH_EXPORT usearch_index_t usearch_init(usearch_init_options_t* options, use
                                            reinterpret_cast<std::uintptr_t>(options->metric), //
                                            metric_punned_signature_t::array_array_k,          //
                                            metric_kind, scalar_kind);
-    if (!metric) {
+    if (metric.missing()) {
         *error = "Unknown metric kind!";
         return NULL;
     }
diff --git a/include/usearch/index_plugins.hpp b/include/usearch/index_plugins.hpp
index 8b1f6f87..25ab8ce4 100644
--- a/include/usearch/index_plugins.hpp
+++ b/include/usearch/index_plugins.hpp
@@ -1401,7 +1401,16 @@ class metric_punned_t {
     inline std::size_t dimensions() const noexcept { return dimensions_; }
     inline metric_kind_t metric_kind() const noexcept { return metric_kind_; }
     inline scalar_kind_t scalar_kind() const noexcept { return scalar_kind_; }
-    explicit inline operator bool() const noexcept { return metric_routed_ && metric_ptr_; }
+    inline explicit operator bool() const noexcept { return metric_routed_ && metric_ptr_; }
+
+    /**
+     *  @brief  Checks fi we've failed to initialized the metric with provided arguments.
+     *
+     *  It's different from `operator bool()` when it comes to explicitly uninitialized metrics.
+     *  It's a common case, where a NULL state is created only to be overwritten later, when
+     *  we recover an old index state from a file or a network.
+     */
+    inline bool missing() const noexcept { return !bool(*this) && metric_kind_ != metric_kind_t::unknown_k; }
 
     inline char const* isa_name() const noexcept {
         if (!*this)
diff --git a/java/cloud/unum/usearch/cloud_unum_usearch_Index.cpp b/java/cloud/unum/usearch/cloud_unum_usearch_Index.cpp
index e5106882..e760b81a 100644
--- a/java/cloud/unum/usearch/cloud_unum_usearch_Index.cpp
+++ b/java/cloud/unum/usearch/cloud_unum_usearch_Index.cpp
@@ -31,7 +31,7 @@ JNIEXPORT jlong JNICALL Java_cloud_unum_usearch_Index_c_1create( //
         index_dense_config_t config(static_cast<std::size_t>(connectivity), static_cast<std::size_t>(expansion_add),
                                     static_cast<std::size_t>(expansion_search));
         metric_punned_t metric(static_cast<std::size_t>(dimensions), metric_kind, quantization);
-        if (!metric) {
+        if (metric.missing()) {
             jclass jc = (*env).FindClass("java/lang/Error");
             if (jc)
                 (*env).ThrowNew(jc, "Failed to initialize the metric!");
diff --git a/javascript/lib.cpp b/javascript/lib.cpp
index e19a769c..0f87a914 100644
--- a/javascript/lib.cpp
+++ b/javascript/lib.cpp
@@ -86,7 +86,7 @@ CompiledIndex::CompiledIndex(Napi::CallbackInfo const& ctx) : Napi::ObjectWrap<C
     bool multi = ctx[6].As<Napi::Boolean>().Value();
 
     metric_punned_t metric(dimensions, metric_kind, quantization);
-    if (!metric) {
+    if (metric.missing()) {
         Napi::TypeError::New(ctx.Env(), "Failed to initialize the metric!").ThrowAsJavaScriptException();
         return;
     }
diff --git a/objc/USearchObjective.mm b/objc/USearchObjective.mm
index 9f7c3ce7..d336fc98 100644
--- a/objc/USearchObjective.mm
+++ b/objc/USearchObjective.mm
@@ -121,7 +121,7 @@ + (instancetype)make:(USearchMetric)metricKind dimensions:(UInt32)dimensions con
 
     index_config_t config(static_cast<std::size_t>(connectivity));
     metric_punned_t metric(dims, to_native_metric(metricKind), to_native_scalar(quantization));
-    if (!metric) {
+    if (metric.missing()) {
         @throw [NSException exceptionWithName:@"Can't create an index"
                                        reason:@"The metric is not supported"
                                      userInfo:nil];
diff --git a/python/lib.cpp b/python/lib.cpp
index f730083a..17413cff 100644
--- a/python/lib.cpp
+++ b/python/lib.cpp
@@ -122,7 +122,7 @@ static dense_index_py_t make_index(             //
         metric_uintptr //
             ? metric_t(dimensions, metric_uintptr, metric_signature, metric_kind, scalar_kind)
             : metric_t(dimensions, metric_kind, scalar_kind);
-    if (!metric)
+    if (metric.missing())
         throw std::invalid_argument("Unsupported metric!");
 
     return index_dense_t::make(metric, config);
diff --git a/rust/lib.cpp b/rust/lib.cpp
index 14f6ccc4..f43477f7 100644
--- a/rust/lib.cpp
+++ b/rust/lib.cpp
@@ -131,7 +131,7 @@ std::unique_ptr<NativeIndex> new_native_index(IndexOptions const& options) {
     metric_kind_t metric_kind = rust_to_cpp_metric(options.metric);
     scalar_kind_t scalar_kind = rust_to_cpp_scalar(options.quantization);
     metric_punned_t metric(options.dimensions, metric_kind, scalar_kind);
-    if (!metric)
+    if (metric.missing())
         throw std::invalid_argument("Unsupported metric or scalar type");
     index_dense_config_t config(options.connectivity, options.expansion_add, options.expansion_search);
     config.multi = options.multi;