diff --git a/plugins/rendermax/renderer_light.cpp b/plugins/rendermax/renderer_light.cpp
index fc7202890..fb5bd8f0e 100644
--- a/plugins/rendermax/renderer_light.cpp
+++ b/plugins/rendermax/renderer_light.cpp
@@ -1043,10 +1043,11 @@ void lightThread::run()
 {
     while(!isDone)
     {
-        {
-            tthread::lock_guard<tthread::mutex> guard(dispatch.occlusionMutex); 
+        {//wait for occlusion (and lights) to be ready
+            tthread::lock_guard<tthread::mutex> guard(dispatch.occlusionMutex);
+            if(!dispatch.occlusionReady)
             dispatch.occlusionDone.wait(dispatch.occlusionMutex);//wait for work
-            if(dispatch.unprocessed.size()==0) //spurious wake-up
+            if(dispatch.unprocessed.size()==0 || !dispatch.occlusionReady) //spurious wake-up
                 continue;
             if(dispatch.occlusion.size()!=canvas.size()) //oh no somebody resized stuff
                 canvas.resize(dispatch.occlusion.size());
@@ -1055,8 +1056,18 @@ void lightThread::run()
         
         { //get my rectangle (any will do)
             tthread::lock_guard<tthread::mutex> guard(dispatch.unprocessedMutex);
+            if (dispatch.unprocessed.size()==0)
+            {
+                //wtf?? why?!
+                continue;
+            }
             myRect=dispatch.unprocessed.top();
             dispatch.unprocessed.pop();
+            if (dispatch.unprocessed.size()==0)
+            {
+                dispatch.occlusionReady=false;
+            }
+            
         }
         work();
         {
@@ -1173,8 +1184,10 @@ void lightThreadDispatch::signalDoneOcclusion()
         tthread::lock_guard<tthread::mutex> guardWrite(writeLock);
         writeCount=0;
     }
-    tthread::lock_guard<tthread::mutex> guard(occlusionMutex);
-    
+    tthread::lock_guard<tthread::mutex> guard1(occlusionMutex);
+    tthread::lock_guard<tthread::mutex> guard2(unprocessedMutex);
+    while(!unprocessed.empty())
+        unprocessed.pop();
     viewPort=getMapViewport();
     int threadCount=threadPool.size();
     int w=viewPort.second.x-viewPort.first.x;
@@ -1189,10 +1202,12 @@ void lightThreadDispatch::signalDoneOcclusion()
             area.second.x=viewPort.first.x+(i+1)*slicew;
         unprocessed.push(area);
     }
+    occlusionReady=true;
     occlusionDone.notify_all();
 }
 
-lightThreadDispatch::lightThreadDispatch( lightingEngineViewscreen* p ):parent(p),lights(parent->lights),occlusion(parent->ocupancy),lightMap(parent->lightMap),writeCount(0)
+lightThreadDispatch::lightThreadDispatch( lightingEngineViewscreen* p ):parent(p),lights(parent->lights),occlusion(parent->ocupancy),
+    lightMap(parent->lightMap),writeCount(0),occlusionReady(false)
 {
 
 }
@@ -1202,6 +1217,11 @@ void lightThreadDispatch::shutdown()
     for(int i=0;i<threadPool.size();i++)
     {
         threadPool[i]->isDone=true;
+        
+    }
+    occlusionDone.notify_all();//if stuck signal that you are done with stuff.
+    for(int i=0;i<threadPool.size();i++)
+    {
         threadPool[i]->myThread->join();
     }
     threadPool.clear();
@@ -1239,3 +1259,8 @@ void lightThreadDispatch::waitForWrites()
         writesDone.wait(writeLock); //if not, wait a bit
     }
 }
+
+lightThreadDispatch::~lightThreadDispatch()
+{
+    shutdown();
+}
diff --git a/plugins/rendermax/renderer_light.hpp b/plugins/rendermax/renderer_light.hpp
index cb43c20be..0f981cf8b 100644
--- a/plugins/rendermax/renderer_light.hpp
+++ b/plugins/rendermax/renderer_light.hpp
@@ -71,7 +71,7 @@ class lightingEngine
 {
 public:
     lightingEngine(renderer_light* target):myRenderer(target){}
-
+    virtual ~lightingEngine(){}
     virtual void reinit()=0;
     virtual void calculate()=0;
 
@@ -145,6 +145,7 @@ public:
 
     tthread::mutex occlusionMutex;
     tthread::condition_variable occlusionDone; //all threads wait for occlusion to finish
+    bool occlusionReady;
     tthread::mutex unprocessedMutex;
     std::stack<DFHack::rect2d> unprocessed; //stack of parts of map where lighting is not finished
     std::vector<rgbf>& occlusion;
@@ -156,6 +157,7 @@ public:
     int writeCount;
 
     lightThreadDispatch(lightingEngineViewscreen* p);
+    ~lightThreadDispatch();
     void signalDoneOcclusion();
     void shutdown();
     void waitForWrites();
diff --git a/plugins/rendermax/rendermax.cpp b/plugins/rendermax/rendermax.cpp
index e03de7ed2..c5fe90a66 100644
--- a/plugins/rendermax/rendermax.cpp
+++ b/plugins/rendermax/rendermax.cpp
@@ -88,7 +88,7 @@ void removeOld()
         INTERPOSE_HOOK(dwarmode_render_hook,render).apply(false);
         INTERPOSE_HOOK(dungeon_render_hook,render).apply(false);
         delete engine;
-
+        engine=0;
     }
     if(current_mode!=MODE_DEFAULT)
         delete df::global::enabler->renderer;
@@ -405,7 +405,8 @@ static command_result rendermax(color_ostream &out, vector <string> & parameters
             out.print("%s\n","Not installed, doing nothing.");
         else
             removeOld();
-        
+        CoreSuspender guard;
+        df::global::gps->force_full_display_count++;
         return CR_OK;
     }
     return CR_WRONG_USAGE;