diff --git a/src/server/game/Globals/ObjectMgr.cpp b/src/server/game/Globals/ObjectMgr.cpp
index b4c84138635..bd3a447b19e 100644
--- a/src/server/game/Globals/ObjectMgr.cpp
+++ b/src/server/game/Globals/ObjectMgr.cpp
@@ -2708,6 +2708,13 @@ void ObjectMgr::LoadInstanceSpawnGroups()
             info.BossStates = states;
 
         uint8 const flags = fields[4].GetUInt8();
+
+        if ((flags & (InstanceSpawnGroupInfo::FLAG_BLOCK_SPAWN | InstanceSpawnGroupInfo::FLAG_ACTIVATE_SPAWN)))
+        {
+            info.Flags = flags & InstanceSpawnGroupInfo::FLAG_BLOCK_SPAWN;
+            TC_LOG_ERROR("sql.sql", "Instance spawn group (%u,%u) FLAG_ACTIVATE_SPAWN and FLAG_BLOCK_SPAWN may not be used together in a single entry - truncated to %u.", instanceMapId, spawnGroupId, info.Flags);
+        }
+
         if (flags & ~InstanceSpawnGroupInfo::FLAG_ALL)
         {
             info.Flags = flags & InstanceSpawnGroupInfo::FLAG_ALL;
diff --git a/src/server/game/Globals/ObjectMgr.h b/src/server/game/Globals/ObjectMgr.h
index 2b4bfd402d9..96a5315f4c4 100644
--- a/src/server/game/Globals/ObjectMgr.h
+++ b/src/server/game/Globals/ObjectMgr.h
@@ -433,9 +433,10 @@ struct TC_GAME_API InstanceSpawnGroupInfo
     enum
     {
         FLAG_ACTIVATE_SPAWN = 0x01,
-        FLAG_BLOCK_SPAWN = 0x02,
+        FLAG_BLOCK_SPAWN    = 0x02,
+        FLAG_FORCE_DESPAWN  = 0x04,
 
-        FLAG_ALL = (FLAG_ACTIVATE_SPAWN | FLAG_BLOCK_SPAWN)
+        FLAG_ALL = (FLAG_ACTIVATE_SPAWN | FLAG_BLOCK_SPAWN | FLAG_FORCE_DESPAWN)
     };
     uint8 BossStateId;
     uint8 BossStates;
diff --git a/src/server/game/Instances/InstanceScript.cpp b/src/server/game/Instances/InstanceScript.cpp
index 8266f9795d4..de41d1bd235 100644
--- a/src/server/game/Instances/InstanceScript.cpp
+++ b/src/server/game/Instances/InstanceScript.cpp
@@ -242,32 +242,49 @@ void InstanceScript::UpdateSpawnGroups()
 {
     if (!_instanceSpawnGroups)
         return;
-    enum states { BLOCK, SPAWN, FORCEBLOCK };
-    std::unordered_map<uint32, states> newStates;
+    enum states : uint8
+    {
+        BLOCK           = 0x0,
+        SPAWN           = 0x1,
+        FORCEBLOCK      = 0x2,
+        FORCEDESPAWN    = 0x4
+    };
+
+    std::unordered_map<uint32, uint8> newStates;
     for (auto it = _instanceSpawnGroups->begin(), end = _instanceSpawnGroups->end(); it != end; ++it)
     {
         InstanceSpawnGroupInfo const& info = *it;
-        states& curValue = newStates[info.SpawnGroupId]; // makes sure there's a BLOCK value in the map
+        uint8& curValue = newStates[info.SpawnGroupId]; // makes sure there's a BLOCK value in the map
         if (curValue == FORCEBLOCK) // nothing will change this
             continue;
         if (!((1 << GetBossState(info.BossStateId)) & info.BossStates))
             continue;
         if (info.Flags & InstanceSpawnGroupInfo::FLAG_BLOCK_SPAWN)
-            curValue = FORCEBLOCK;
-        else if (info.Flags & InstanceSpawnGroupInfo::FLAG_ACTIVATE_SPAWN)
-            curValue = SPAWN;
+            curValue |= FORCEBLOCK;
+        if (info.Flags & InstanceSpawnGroupInfo::FLAG_ACTIVATE_SPAWN)
+            curValue |= SPAWN;
+        if (info.Flags & InstanceSpawnGroupInfo::FLAG_FORCE_DESPAWN)
+            curValue |= FORCEDESPAWN;
     }
     for (auto const& pair : newStates)
     {
         uint32 const groupId = pair.first;
-        bool const doSpawn = (pair.second == SPAWN);
-        if (instance->IsSpawnGroupActive(groupId) == doSpawn)
-            continue; // nothing to do here
-        // if we should spawn group, then spawn it...
-        if (doSpawn)
+        uint8 state = pair.second;
+        // Spawn group is already active, skip
+        if (instance->IsSpawnGroupActive(groupId) == (state & SPAWN))
+            continue;
+
+        // Spawn group shall be spawned, spawn it
+        if (state & SPAWN)
             instance->SpawnGroupSpawn(groupId);
-        else // otherwise, set it as inactive so it no longer respawns (but don't despawn it)
+
+        // Spawn group shall be disabled, disable it
+        if (state & FORCEBLOCK)
             instance->SetSpawnGroupInactive(groupId);
+
+        // Spawn group shall be despawned, despawn it
+        if (state & FORCEDESPAWN)
+            instance->SpawnGroupDespawn(groupId);
     }
 }
 
@@ -349,10 +366,10 @@ bool InstanceScript::SetBossState(uint32 id, EncounterState state)
             return false;
         }
 
-		else
-		{
-			if (bossInfo->state == state)
-				return false;
+        else
+        {
+            if (bossInfo->state == state)
+                return false;
 
             if (bossInfo->state == DONE)
             {
@@ -360,11 +377,11 @@ bool InstanceScript::SetBossState(uint32 id, EncounterState state)
                 return false;
             }
 
-			if (state == DONE)
-				for (GuidSet::iterator i = bossInfo->minion.begin(); i != bossInfo->minion.end(); ++i)
-					if (Creature* minion = instance->GetCreature(*i))
-						if (minion->isWorldBoss() && minion->IsAlive())
-							return false;
+            if (state == DONE)
+                for (GuidSet::iterator i = bossInfo->minion.begin(); i != bossInfo->minion.end(); ++i)
+                    if (Creature * minion = instance->GetCreature(*i))
+                        if (minion->isWorldBoss() && minion->IsAlive())
+                            return false;
 
             if (instance->IsRaid())
             {