diff --git a/src/actor.h b/src/actor.h
index 9e96ab2c2..8741a9597 100644
--- a/src/actor.h
+++ b/src/actor.h
@@ -576,8 +576,7 @@ public:
 	~AActor ();
 
 	void Serialize (FArchive &arc);
-	void PostSerialize();
-
+	
 	static AActor *StaticSpawn (PClassActor *type, const DVector3 &pos, replace_t allowreplacement, bool SpawningMapThing = false);
 
 	inline AActor *GetDefault () const
diff --git a/src/dthinker.h b/src/dthinker.h
index c08ea9d83..10a53309d 100644
--- a/src/dthinker.h
+++ b/src/dthinker.h
@@ -69,7 +69,6 @@ public:
 	virtual ~DThinker ();
 	virtual void Tick ();
 	virtual void PostBeginPlay ();	// Called just before the first tick
-	virtual void PostSerialize() {}
 	size_t PropagateMark();
 	
 	void ChangeStatNum (int statnum);
diff --git a/src/g_level.cpp b/src/g_level.cpp
index 7a8c79d62..141932c22 100644
--- a/src/g_level.cpp
+++ b/src/g_level.cpp
@@ -1531,8 +1531,9 @@ void G_SerializeLevel (FArchive &arc, bool hubLoad)
 
 	FBehavior::StaticSerializeModuleStates (arc);
 	if (arc.IsLoading()) interpolator.ClearInterpolations();
+	P_SerializeWorld(arc);
 	P_SerializeThinkers (arc, hubLoad);
-	P_SerializeWorld (arc);
+	P_SerializeWorldActors(arc);	// serializing actor pointers in the world data must be done after SerializeWorld has restored the entire sector state, otherwise LinkToWorld may fail.
 	P_SerializePolyobjs (arc);
 	P_SerializeSubsectors(arc);
 	StatusBar->Serialize (arc);
@@ -1579,13 +1580,6 @@ void G_SerializeLevel (FArchive &arc, bool hubLoad)
 	P_SerializeSounds (arc);
 	if (arc.IsLoading())
 	{
-		FThinkerIterator it(RUNTIME_CLASS(DThinker));
-		DThinker *th;
-		while ((th = it.Next()))
-		{
-			th->PostSerialize();
-		}
-
 		for (i = 0; i < numsectors; i++)
 		{
 			P_Recalculate3DFloors(&sectors[i]);
diff --git a/src/p_mobj.cpp b/src/p_mobj.cpp
index bc4501834..46bc320df 100644
--- a/src/p_mobj.cpp
+++ b/src/p_mobj.cpp
@@ -397,6 +397,9 @@ void AActor::Serialize(FArchive &arc)
 
 	if (arc.IsLoading ())
 	{
+		touching_sectorlist = NULL;
+		LinkToWorld(false, Sector);
+
 		AddToHash ();
 		SetShade (fillcolor);
 		if (player)
@@ -413,17 +416,11 @@ void AActor::Serialize(FArchive &arc)
 				Speed = GetDefault()->Speed;
 			}
 		}
+		ClearInterpolation();
+		UpdateWaterLevel(false);
 	}
 }
 
-void AActor::PostSerialize()
-{
-	touching_sectorlist = NULL;
-	LinkToWorld(false, Sector);
-	ClearInterpolation();
-	UpdateWaterLevel(false);
-}
-
 AActor::AActor () throw()
 {
 }
diff --git a/src/p_saveg.cpp b/src/p_saveg.cpp
index 5cec1c815..55320e056 100644
--- a/src/p_saveg.cpp
+++ b/src/p_saveg.cpp
@@ -363,9 +363,7 @@ void P_SerializeWorld (FArchive &arc)
 		arc << sec->damageamount;
 		arc << sec->damageinterval
 			<< sec->leakydamage
-			<< sec->damagetype;
-		arc << sec->SoundTarget
-			<< sec->SecActTarget
+			<< sec->damagetype
 			<< sec->sky
 			<< sec->MoreFlags
 			<< sec->Flags
@@ -453,6 +451,22 @@ void P_SerializeWorld (FArchive &arc)
 	P_CollectLinkedPortals();
 }
 
+void P_SerializeWorldActors(FArchive &arc)
+{
+	int i, j;
+	sector_t *sec;
+
+	for (i = 0, sec = sectors; i < numsectors; i++, sec++)
+	{
+		arc << sec->SoundTarget
+			<< sec->SecActTarget;
+	}
+	for (auto &s : sectorPortals)
+	{
+		arc << s.mSkybox;
+	}
+}
+
 void extsector_t::Serialize(FArchive &arc)
 {
 	arc << FakeFloor.Sectors
diff --git a/src/p_saveg.h b/src/p_saveg.h
index 9ae32cc87..c6c056004 100644
--- a/src/p_saveg.h
+++ b/src/p_saveg.h
@@ -41,6 +41,7 @@ struct PNGHandle;
 // These are the load / save game routines.
 // Also see farchive.(h|cpp)
 void P_SerializePlayers (FArchive &arc, bool fakeload);
+void P_SerializeWorldActors(FArchive &arc);
 void P_SerializeWorld (FArchive &arc);
 void P_SerializeThinkers (FArchive &arc, bool);
 void P_SerializePolyobjs (FArchive &arc);
diff --git a/src/portal.cpp b/src/portal.cpp
index 7e192d467..3dfd9a050 100644
--- a/src/portal.cpp
+++ b/src/portal.cpp
@@ -230,8 +230,7 @@ FArchive &operator<< (FArchive &arc, FSectorPortal &port)
 		<< port.mOrigin
 		<< port.mDestination
 		<< port.mDisplacement
-		<< port.mPlaneZ
-		<< port.mSkybox;
+		<< port.mPlaneZ;
 	return arc;
 }
 
diff --git a/src/version.h b/src/version.h
index 2550ce2e2..46c8abf66 100644
--- a/src/version.h
+++ b/src/version.h
@@ -72,11 +72,11 @@ const char *GetVersionString();
 // SAVESIG should match SAVEVER.
 
 // MINSAVEVER is the minimum level snapshot version that can be loaded.
-#define MINSAVEVER	4539
+#define MINSAVEVER	4540
 
 // Use 4500 as the base git save version, since it's higher than the
 // SVN revision ever got.
-#define SAVEVER 4539
+#define SAVEVER 4540
 
 #define SAVEVERSTRINGIFY2(x) #x
 #define SAVEVERSTRINGIFY(x) SAVEVERSTRINGIFY2(x)