diff --git a/texthook/engine/match32.cc b/texthook/engine/match32.cc
index 47077d5..aae1470 100644
--- a/texthook/engine/match32.cc
+++ b/texthook/engine/match32.cc
@@ -179,8 +179,7 @@ bool DetermineEngineByFile1()
     InsertArtemisHook();
     return true;
   }
-  if (Util::CheckFile(L"*.int")) {
-    InsertCatSystemHook();
+  if (Util::CheckFile(L"*.int") && InsertCatSystemHook()) {
     return true;
   }
   if (Util::CheckFile(L"message.dat")) {