diff --git a/interop/src/cpp/DeserializerBase.h b/interop/src/cpp/DeserializerBase.h
index eb87c410949f66bc863826b69169f18c05d2ccb7..7f62a8768b5b73acca635d776a24f49e0eb08eb2 100644
--- a/interop/src/cpp/DeserializerBase.h
+++ b/interop/src/cpp/DeserializerBase.h
@@ -52,8 +52,7 @@ inline const char *tagName(InteropTag tag)
   case InteropTag::INTEROP_TAG_OBJECT:
     return "OBJECT";
   }
-  fprintf(stderr, "tag name %d is wrong\n", tag);
-  throw "Error";
+  INTEROP_FATAL("Fatal error");
 }
 
 inline const char *tagNameExact(InteropTag tag)
@@ -75,8 +74,7 @@ inline const char *tagNameExact(InteropTag tag)
   case InteropTag::INTEROP_TAG_OBJECT:
     return "INTEROP_TAG_OBJECT";
   }
-  fprintf(stderr, "tag name %d is wrong\n", tag);
-  throw "Error";
+  INTEROP_FATAL("Fatal error");
 }
 
 inline InteropFunction makeArkFunctionFromId(InteropInt32 id) {
@@ -464,8 +462,7 @@ public:
     }
     else
     {
-      fprintf(stderr, "Bad number tag %d\n", result.tag);
-      throw "Unknown number tag";
+      INTEROP_FATAL("Fatal error");
     }
     return result;
   }
@@ -503,8 +500,7 @@ public:
     }
     default:
     {
-      fprintf(stderr, "Bad length tag %d\n", result.type);
-      throw "Error";
+      INTEROP_FATAL("Fatal error");
     }
     }
     return result;
diff --git a/interop/src/cpp/SerializerBase.h b/interop/src/cpp/SerializerBase.h
index 951ccac942f71fb2d48c25e8d90ae52c17fe07d3..8d638146613b76db7f99a404bfd6fd7c87019801 100644
--- a/interop/src/cpp/SerializerBase.h
+++ b/interop/src/cpp/SerializerBase.h
@@ -172,8 +172,7 @@ public:
         } else if (value.tag == InteropTag::INTEROP_TAG_FLOAT32) {
             writeFloat32(value.f32);
         } else {
-            fprintf(stderr, "Bad number tag %d\n", value.tag);
-            throw "Unknown number tag";
+            INTEROP_FATAL("Unknown tag number");
         }
     }
 
diff --git a/interop/src/cpp/ets/convertors-ets.cc b/interop/src/cpp/ets/convertors-ets.cc
index 455548eeb2457f4a254bc9d30b55186bfa5b2180..d6f66171c61f3c7aac42a83ba8c2eaef3cdecde8 100644
--- a/interop/src/cpp/ets/convertors-ets.cc
+++ b/interop/src/cpp/ets/convertors-ets.cc
@@ -111,7 +111,6 @@ const std::vector<std::tuple<std::string, std::string, void*, int>>& EtsExports:
     auto it = implementations.find(module);
     if (it == implementations.end()) {
         LOGE("Module %s is not registered", module.c_str());
-        throw "Fatal error";
     }
     return it->second;
 }
@@ -130,7 +129,6 @@ void EtsExports::setClasspath(const char* module, const char *classpath) {
         classpaths.insert(std::make_pair(module, classpath));
     } else {
         LOGE("Classpath for module %s was redefined", module);
-        throw "Fatal error";
     }
 }
 
@@ -151,5 +149,4 @@ const std::string& EtsExports::getClasspath(const std::string& module) {
         return defaultClasspath->second;
     }
     LOGE("Classpath for module %s was not registered", module.c_str());
-    throw "Fatal error";
 }
diff --git a/interop/src/cpp/interop-types.h b/interop/src/cpp/interop-types.h
index b8aeefb3465d2f0472f39254265831a1ddcd69c4..ff0f53b4f2d4111d9ead0ea5d0b98f1f26936597 100644
--- a/interop/src/cpp/interop-types.h
+++ b/interop/src/cpp/interop-types.h
@@ -3,6 +3,8 @@
 
 #include <stdint.h>
 
+#define INTEROP_FATAL(msg, ...) fprintf(stderr, msg "\n", ##__VA_ARGS__); assert(false);
+
 typedef enum InteropTag
 {
   INTEROP_TAG_UNDEFINED = 101,
diff --git a/interop/src/cpp/types/signatures.cc b/interop/src/cpp/types/signatures.cc
index 3d035719f51673ed3183d266358fa9bc4b0fe31a..9e16aa58666ef540d1ba9b4a8fa3206cf736130a 100644
--- a/interop/src/cpp/types/signatures.cc
+++ b/interop/src/cpp/types/signatures.cc
@@ -78,7 +78,6 @@ std::string sigType(const std::string &type) {
     KOALA_INTEROP_TYPEDEFS("sigType", "jni")
 #endif
     fprintf(stderr, "Unhandled type: %s\n", type.c_str());
-    throw "Error";
 }
 
 std::string codeType(const std::string &type) {
@@ -88,7 +87,6 @@ std::string codeType(const std::string &type) {
     KOALA_INTEROP_TYPEDEFS("codeType", "jni")
 #endif
     fprintf(stderr, "Unhandled type: %s\n", type.c_str());
-    throw "Error";
 }
 
 std::string convertType(const char* name, const char* koalaType) {