diff --git a/src/p_local.h b/src/p_local.h
index 0dd0dca68..82f4580b9 100644
--- a/src/p_local.h
+++ b/src/p_local.h
@@ -221,7 +221,7 @@ void	P_FakeZMovement (AActor *mo);
 bool	P_TryMove(AActor* thing, const DVector2 &pos, int dropoff, const secplane_t * onfloor, FCheckPosition &tm, bool missileCheck = false);
 bool	P_TryMove(AActor* thing, const DVector2 &pos, int dropoff, const secplane_t * onfloor = NULL);
 
-bool	P_CheckMove(AActor *thing, const DVector2 &pos);
+bool	P_CheckMove(AActor *thing, const DVector2 &pos, bool dropoff = false);
 void	P_ApplyTorque(AActor *mo);
 
 bool	P_TeleportMove(AActor* thing, const DVector3 &pos, bool telefrag, bool modifyactor = true);	// [RH] Added z and telefrag parameters
diff --git a/src/p_map.cpp b/src/p_map.cpp
index 61e651ce6..15cd5eb5b 100644
--- a/src/p_map.cpp
+++ b/src/p_map.cpp
@@ -2410,7 +2410,7 @@ bool P_TryMove(AActor *thing, const DVector2 &pos,
 //
 //==========================================================================
 
-bool P_CheckMove(AActor *thing, const DVector2 &pos)
+bool P_CheckMove(AActor *thing, const DVector2 &pos, bool dropoff)
 {
 	FCheckPosition tm;
 	double		newz = thing->Z();
@@ -2469,6 +2469,17 @@ bool P_CheckMove(AActor *thing, const DVector2 &pos)
 					return false;
 				}
 			}
+			else if (dropoff)
+			{
+				const DVector3 oldpos = thing->Pos();
+				thing->SetOrigin(pos.X, pos.Y, newz, true);
+				bool hcheck = (newz - thing->MaxDropOffHeight > thing->floorz);
+				thing->SetOrigin(oldpos, true);
+				if (hcheck && !(thing->flags & MF_FLOAT) && !(i_compatflags & COMPATF_DROPOFF))
+				{
+					return false;
+				}
+			}
 		}
 
 		if (thing->flags2 & MF2_CANTLEAVEFLOORPIC
diff --git a/src/thingdef/thingdef_codeptr.cpp b/src/thingdef/thingdef_codeptr.cpp
index d0a157932..cc4ffd33b 100644
--- a/src/thingdef/thingdef_codeptr.cpp
+++ b/src/thingdef/thingdef_codeptr.cpp
@@ -6707,7 +6707,7 @@ DEFINE_ACTION_FUNCTION_PARAMS(AActor, A_CheckBlock)
 	if (flags & CBF_DROPOFF)
 	{
 		mobj->SetZ(pos.Z);
-		checker = P_CheckMove(mobj, pos);
+		checker = P_CheckMove(mobj, pos, true);
 		mobj->SetZ(oldpos.Z);
 	}
 	else
@@ -6742,8 +6742,10 @@ DEFINE_ACTION_FUNCTION_PARAMS(AActor, A_CheckBlock)
 	}
 	//[MC] I don't know why I let myself be persuaded not to include a flag.
 	//If an actor is loaded with pointers, they don't really have any options to spare.
+	//Also, fail if a dropoff or a step is too great to pass over when checking for dropoffs.
 
-	if ((!(flags & CBF_NOACTORS) && (mobj->BlockingMobj)) || (!(flags & CBF_NOLINES) && mobj->BlockingLine != NULL))
+	if ((!(flags & CBF_NOACTORS) && (mobj->BlockingMobj)) || (!(flags & CBF_NOLINES) && mobj->BlockingLine != NULL) ||
+		((flags & CBF_DROPOFF) && !checker))
 	{
 		ACTION_RETURN_STATE(block);
 	}