diff --git a/srtcore/api.cpp b/srtcore/api.cpp
index bb5dd64fe..ff55f8018 100644
--- a/srtcore/api.cpp
+++ b/srtcore/api.cpp
@@ -180,6 +180,7 @@ srt::CUDTUnited::CUDTUnited()
     , m_InitLock()
     , m_iInstanceCount(0)
     , m_bGCStatus(false)
+    , m_bImplicitStartup(false)
     , m_ClosedSockets()
 {
     // Socket ID MUST start from a random value
@@ -198,12 +199,15 @@ srt::CUDTUnited::CUDTUnited()
 
 srt::CUDTUnited::~CUDTUnited()
 {
-    // Call it if it wasn't called already.
-    // This will happen at the end of main() of the application,
-    // when the user didn't call srt_cleanup().
-    if (m_bGCStatus)
     {
-        cleanup();
+        // If an implicit startup was called, then call a matching cleanup
+        // This will happen at the end of main() of the application,
+        // when the user didn't call srt_cleanup() before using the library.
+        ScopedLock gcinit(m_InitLock);
+        if (m_bImplicitStartup)
+        {
+            cleanup();
+        }
     }
 
     releaseMutex(m_GlobControlLock);
@@ -233,15 +237,24 @@ string srt::CUDTUnited::CONID(SRTSOCKET sock)
     return os.str();
 }
 
-int srt::CUDTUnited::startup()
+void srt::CUDTUnited::implicitStartup()
 {
     ScopedLock gcinit(m_InitLock);
     if (m_bGCStatus)
-        return 1;
+        return;
+    m_bImplicitStartup = true;
+    startup();
+}
 
+int srt::CUDTUnited::startup()
+{
+    ScopedLock gcinit(m_InitLock);
     if (m_iInstanceCount++ > 0)
         return 1;
 
+    if (m_bGCStatus)
+        return 1;
+
         // Global initialization code
 #ifdef _WIN32
     WORD    wVersionRequested;
@@ -299,6 +312,7 @@ int srt::CUDTUnited::cleanup()
     m_GCThread.join();
 
     m_bGCStatus = false;
+    m_bImplicitStartup = false;
 
     // Global destruction code
 #ifdef _WIN32
@@ -3469,7 +3483,7 @@ int srt::CUDT::cleanup()
 
 SRTSOCKET srt::CUDT::socket()
 {
-    uglobal().startup();
+    uglobal().implicitStartup();
 
     try
     {
@@ -3519,7 +3533,7 @@ srt::CUDTGroup& srt::CUDT::newGroup(const int type)
 SRTSOCKET srt::CUDT::createGroup(SRT_GROUP_TYPE gt)
 {
     // Doing the same lazy-startup as with srt_create_socket()
-    uglobal().startup();
+    uglobal().implicitStartup();
 
     try
     {
diff --git a/srtcore/api.h b/srtcore/api.h
index 48e7827f8..9779ec8ca 100644
--- a/srtcore/api.h
+++ b/srtcore/api.h
@@ -428,6 +428,7 @@ class CUDTUnited
     CUDTSocket* locateSocket_LOCKED(SRTSOCKET u);
     CUDTSocket* locatePeer(const sockaddr_any& peer, const SRTSOCKET id, int32_t isn);
 
+    void implicitStartup();
 #if ENABLE_BONDING
     CUDTGroup* locateAcquireGroup(SRTSOCKET u, ErrorHandling erh = ERH_RETURN);
     CUDTGroup* acquireSocketsGroup(CUDTSocket* s);
@@ -542,6 +543,8 @@ class CUDTUnited
     int         m_iInstanceCount; // number of startup() called by application
     SRT_ATTR_GUARDED_BY(m_InitLock)
     bool        m_bGCStatus;      // if the GC thread is working (true)
+    SRT_ATTR_GUARDED_BY(m_InitLock)
+    bool        m_bImplicitStartup; // if startup was implicitly called
 
     SRT_ATTR_GUARDED_BY(m_InitLock)
     sync::CThread m_GCThread;