diff --git a/src/core/coreav.cpp b/src/core/coreav.cpp
index 6dc38786a..cbb02efec 100644
--- a/src/core/coreav.cpp
+++ b/src/core/coreav.cpp
@@ -90,7 +90,14 @@ void CoreAV::answerCall(uint32_t friendNum)
 
 void CoreAV::startCall(uint32_t friendId, bool video)
 {
-    assert(!calls.contains(friendId));
+    if(calls.contains(friendId))
+    {
+        qWarning() << QString("Can't start call with %1, we're already in this call!").arg(friendId);
+        emit avCallFailed(friendId);
+        return;
+    }
+
+    qDebug() << QString("Starting call with %1").arg(friendId);
     uint32_t videoBitrate = video ? VIDEO_DEFAULT_BITRATE : 0;
     if (!toxav_call(toxav, friendId, AUDIO_DEFAULT_BITRATE, videoBitrate, nullptr))
     {
@@ -311,10 +318,16 @@ void CoreAV::resetCallSources()
     }
 }
 
-void CoreAV::callCallback(ToxAV*, uint32_t friendNum, bool audio, bool video, void *_self)
+void CoreAV::callCallback(ToxAV* toxav, uint32_t friendNum, bool audio, bool video, void *_self)
 {
     CoreAV* self = static_cast<CoreAV*>(_self);
-    const auto& callIt = calls.insert({friendNum, video, *self});
+    if (self->calls.contains(friendNum))
+    {
+        qWarning() << QString("Rejecting call invite from %1, we're already in that call!").arg(friendNum);
+        toxav_call_control(toxav, friendNum, TOXAV_CALL_CONTROL_CANCEL, nullptr);
+        return;
+    }
+    const auto& callIt = self->calls.insert({friendNum, video, *self});
 
     // We don't get a state callback when answering, so fill the state ourselves in advance
     int state = 0;
diff --git a/src/widget/form/chatform.cpp b/src/widget/form/chatform.cpp
index 8bfab042e..7b1d3cad9 100644
--- a/src/widget/form/chatform.cpp
+++ b/src/widget/form/chatform.cpp
@@ -258,8 +258,7 @@ void ChatForm::onAvInvite(uint32_t FriendId, bool video)
 
     qDebug() << "onAvInvite";
 
-    callButton->disconnect();
-    videoButton->disconnect();
+    disableCallButtons();
     if (video)
     {
         callConfirm = new CallConfirmWidget(videoButton, *f);
@@ -310,8 +309,7 @@ void ChatForm::onAvStart(uint32_t FriendId, bool video)
 
     audioInputFlag = true;
     audioOutputFlag = true;
-    callButton->disconnect();
-    videoButton->disconnect();
+    disableCallButtons();
 
     if (video)
     {
@@ -418,8 +416,7 @@ void ChatForm::onAvStarting(uint32_t FriendId, bool video)
 
     qDebug() << "onAvStarting";
 
-    callButton->disconnect();
-    videoButton->disconnect();
+    disableCallButtons();
     if (video)
     {
         callButton->setObjectName("grey");
@@ -489,7 +486,6 @@ void ChatForm::onAvRequestTimeout(uint32_t FriendId)
 
     enableCallButtons();
     stopCounter();
-
     hideNetcam();
 }
 
@@ -520,6 +516,7 @@ void ChatForm::onAvRejected(uint32_t FriendId)
     callConfirm = nullptr;
 
     enableCallButtons();
+    stopCounter();
 
     insertChatMessage(ChatMessage::createChatInfoMessage(tr("Call rejected"),
                                                          ChatMessage::INFO,
@@ -587,6 +584,7 @@ void ChatForm::onRejectCallTriggered()
     emit rejectCall(f->getFriendID());
 
     enableCallButtons();
+    stopCounter();
 }
 
 void ChatForm::onCallTriggered()
@@ -643,6 +641,31 @@ void ChatForm::enableCallButtons()
     audioInputFlag = false;
     audioOutputFlag = false;
 
+    disableCallButtons();
+
+    if (disableCallButtonsTimer == nullptr)
+    {
+        disableCallButtonsTimer = new QTimer();
+        connect(disableCallButtonsTimer, SIGNAL(timeout()),
+                this, SLOT(onEnableCallButtons()));
+        disableCallButtonsTimer->start(1500); // 1.5sec
+        qDebug() << "timer started!!";
+    }
+
+}
+
+void ChatForm::disableCallButtons()
+{
+    qDebug() << "disableCallButtons";
+
+    // Prevents race enable / disable / onEnable, when it should be disabled
+    if (disableCallButtonsTimer)
+    {
+        disableCallButtonsTimer->stop();
+        delete disableCallButtonsTimer;
+        disableCallButtonsTimer = nullptr;
+    }
+
     micButton->setObjectName("grey");
     micButton->style()->polish(micButton);
     micButton->setToolTip("");
@@ -660,16 +683,6 @@ void ChatForm::enableCallButtons()
     videoButton->style()->polish(videoButton);
     videoButton->setToolTip("");
     videoButton->disconnect();
-
-    if (disableCallButtonsTimer == nullptr)
-    {
-        disableCallButtonsTimer = new QTimer();
-        connect(disableCallButtonsTimer, SIGNAL(timeout()),
-                this, SLOT(onEnableCallButtons()));
-        disableCallButtonsTimer->start(1500); // 1.5sec
-        qDebug() << "timer started!!";
-    }
-
 }
 
 void ChatForm::onEnableCallButtons()
diff --git a/src/widget/form/chatform.h b/src/widget/form/chatform.h
index 11081795e..6a0bd43e8 100644
--- a/src/widget/form/chatform.h
+++ b/src/widget/form/chatform.h
@@ -128,6 +128,7 @@ private:
     QString secondsToDHMS(quint32 duration);
     CallConfirmWidget *callConfirm;
     void enableCallButtons();
+    void disableCallButtons();
     bool isTyping;
     void SendMessageStr(QString msg);
 };