diff --git a/winmonmon.cc b/winmonmon.cc
index c54a00c2bd6b490aba87b9f279913b0fd21625f0..b0184e73386a6a4b1521c58be1afbbf84f46aad6 100755
--- a/winmonmon.cc
+++ b/winmonmon.cc
@@ -31,7 +31,7 @@ int check_once() {
     auto mon_proc_count = 0;
     for(auto && pname : win32_ps()) {
         std::transform(pname.begin(), pname.end(), pname.begin(),[](unsigned char c){ return std::tolower(c); });
-        if(pname.substr(0, 3) == "mon")
+        if(pname.substr(0, 8) == "monagent")
             mon_proc_count++;
     }
     if(mon_proc_count >= 4) return 0;