diff --git a/cleo_plugins/DebugUtils/DebugUtils.cpp b/cleo_plugins/DebugUtils/DebugUtils.cpp
index f96e700b..bd999f82 100644
--- a/cleo_plugins/DebugUtils/DebugUtils.cpp
+++ b/cleo_plugins/DebugUtils/DebugUtils.cpp
@@ -232,8 +232,8 @@ class DebugUtils
         }
         else // breakpoint formatted name string
         {
-            auto format = CLEO_ReadStringOpcodeParam(thread);
-            name = CLEO_ReadParamsFormatted(thread, format);
+            OPCODE_READ_PARAM_STRING_FORMATTED(nameStr);
+            name = nameStr;
         }
 
         pausedScripts.emplace_back(thread, name.c_str());
@@ -262,8 +262,7 @@ class DebugUtils
             return OR_CONTINUE;
         }
 
-        auto format = CLEO_ReadStringOpcodeParam(thread);
-        auto message = CLEO_ReadParamsFormatted(thread, format);
+        OPCODE_READ_PARAM_STRING_FORMATTED(message);
 
         CLEO_Log(eLogLevel::Debug, message);
         return OR_CONTINUE;
diff --git a/cleo_plugins/FileSystemOperations/FileSystemOperations.cpp b/cleo_plugins/FileSystemOperations/FileSystemOperations.cpp
index 6b09d0b1..140aabfc 100644
--- a/cleo_plugins/FileSystemOperations/FileSystemOperations.cpp
+++ b/cleo_plugins/FileSystemOperations/FileSystemOperations.cpp
@@ -355,8 +355,7 @@ class FileSystemOperations
     static OpcodeResult WINAPI opcode_0AD9(CRunningScript* thread)
     {
         OPCODE_READ_PARAM_FILE_HANDLE(handle);
-        OPCODE_READ_PARAM_STRING(format);
-        static char text[4 * MAX_STR_LEN]; CLEO_ReadParamsFormatted(thread, format, text, MAX_STR_LEN);
+        OPCODE_READ_PARAM_STRING_FORMATTED(text);
         
         auto ok = File::writeString(handle, text);
         if (!ok)
diff --git a/cleo_sdk/CLEO_Utils.h b/cleo_sdk/CLEO_Utils.h
index 3555d8e6..93f42f24 100644
--- a/cleo_sdk/CLEO_Utils.h
+++ b/cleo_sdk/CLEO_Utils.h
@@ -691,9 +691,11 @@ namespace CLEO
     #define OPCODE_READ_PARAM_STRING_LEN(_varName, _maxLen) char _buff_##_varName[_maxLen + 1]; const char* ##_varName = _readParamText(thread, _buff_##_varName, _maxLen + 1); if(##_varName != nullptr) ##_varName = _buff_##_varName; if(!_paramWasString()) { return OpcodeResult::OR_INTERRUPT; }
 
     #define OPCODE_READ_PARAM_STRING_FORMATTED(_varName) char _buff_format_##_varName[MAX_STR_LEN + 1]; const char* _format_##_varName = _readParamText(thread, _buff_format_##_varName, MAX_STR_LEN + 1); if(!_paramWasString()) { return OpcodeResult::OR_INTERRUPT; } \
-        char _varName[2 * MAX_STR_LEN + 1]; char* _varName##Ok = CLEO_ReadParamsFormatted(thread, _buff_format_##_varName, _varName, sizeof(_varName));
+        char _varName[2 * MAX_STR_LEN + 1]; char* _varName##Ok = CLEO_ReadParamsFormatted(thread, _buff_format_##_varName, _varName, sizeof(_varName)); \
+        if(_varName##Ok == nullptr) { SHOW_ERROR("Invalid formatted string in script %s \nScript suspended.", CLEO::ScriptInfoStr(thread).c_str()); return thread->Suspend(); }
 
-    #define OPCODE_READ_PARAMS_FORMATTED(_format, _varName) char _varName[2 * MAX_STR_LEN + 1]; char* _varName##Ok = CLEO_ReadParamsFormatted(thread, _format, _varName, sizeof(_varName));
+    #define OPCODE_READ_PARAMS_FORMATTED(_format, _varName) char _varName[2 * MAX_STR_LEN + 1]; char* _varName##Ok = CLEO_ReadParamsFormatted(thread, _format, _varName, sizeof(_varName)); \
+        if(_varName##Ok == nullptr) { SHOW_ERROR("Invalid formatted string in script %s \nScript suspended.", CLEO::ScriptInfoStr(thread).c_str()); return thread->Suspend(); }
 
     #define OPCODE_READ_PARAM_FILEPATH(_varName) char _buff_##_varName[512]; const char* ##_varName = _readParamText(thread, _buff_##_varName, 512); if(##_varName != nullptr) ##_varName = _buff_##_varName; if(_paramWasString()) CLEO_ResolvePath(thread, _buff_##_varName, 512); else return OpcodeResult::OR_INTERRUPT; \
         if(!FilepathIsSafe(thread, ##_varName)) { SHOW_ERROR("Forbidden file path '%s' outside game directories in script %s \nScript suspended.", ##_varName, ScriptInfoStr(thread).c_str()); return thread->Suspend(); }
diff --git a/source/CCustomOpcodeSystem.cpp b/source/CCustomOpcodeSystem.cpp
index 58ecbe4e..a55e34a6 100644
--- a/source/CCustomOpcodeSystem.cpp
+++ b/source/CCustomOpcodeSystem.cpp
@@ -481,7 +481,7 @@ namespace CLEO
 		// invalid input arguments
 		if(outputStr == nullptr || len == 0)
 		{
-			LOG_WARNING(thread, "ReadFormattedString invalid input arg(s)");
+			LOG_WARNING(thread, "ReadFormattedString invalid input arg(s) in script %s", ((CCustomScript*)thread)->GetInfoStr().c_str());
 			SkipUnusedVarArgs(thread);
 			return -1; // error
 		}
@@ -498,10 +498,19 @@ namespace CLEO
 
 				if (*iter == '%')
 				{
+					// end of format string
+					if (iter[1] == '\0')
+					{
+						LOG_WARNING(thread, "ReadFormattedString encountered incomplete format specifier in script %s", ((CCustomScript*)thread)->GetInfoStr().c_str());
+						SkipUnusedVarArgs(thread);
+						return -1; // error
+					}
+
+					// escaped % character
 					if (iter[1] == '%')
 					{
 						if (written++ >= len) goto _ReadFormattedString_OutOfMemory;
-						*outIter++ = '%'; /* "%%"->'%' */
+						*outIter++ = '%';
 						iter += 2;
 						continue;
 					}