diff --git a/src/libs/ck-libs/collide/collide_util.C b/src/libs/ck-libs/collide/collide_util.C
index 3148fdbf5c..5a533f3a59 100644
--- a/src/libs/ck-libs/collide/collide_util.C
+++ b/src/libs/ck-libs/collide/collide_util.C
@@ -49,7 +49,7 @@ void CollideGrid3d::init(const vector3d &Norigin,//Grid voxel corner 0,0,0
     sizes[i]=desiredSize[i];
 #endif
     ((double *)scales)[i]=1.0/((double *)sizes)[i];
-    testMapping(*this,i,((double *)origin)[i],((double *)sizes)[i]);
+    //testMapping(*this,i,((double *)origin)[i],((double *)sizes)[i]);
   }
 
 }
diff --git a/src/libs/ck-libs/collide/collidecharm.C b/src/libs/ck-libs/collide/collidecharm.C
index 68b4440579..b6e928548d 100644
--- a/src/libs/ck-libs/collide/collidecharm.C
+++ b/src/libs/ck-libs/collide/collidecharm.C
@@ -4,6 +4,7 @@
  */
 #include "charm++.h"
 #include "collidecharm_impl.h"
+#include <iostream>
 
 #define COLLIDE_TRACE 0
 #if COLLIDE_TRACE
@@ -51,6 +52,17 @@ CkGroupID CollideDistributedClient(CkCallback clientCb)
   return cl;
 }
 
+/// Call this on all processors at restart to reinitialize the Collision client
+/// with correct clientFn and clientParam.
+void CollideSerialClientRestart(
+  CollideHandle h,
+  CollisionClientFn clientFn,
+  void *clientParam )
+{
+  CProxy_collideMgr mgr(h);
+  mgr.ckLocalBranch()->reinitClient(clientFn, clientParam);
+}
+
 /// Create a collider group to contribute objects to.
 ///  Should be called on processor 0.
 CollideHandle CollideCreate(const CollideGrid3d &gridMap,
@@ -329,7 +341,7 @@ static const char * voxName(const CkIndex3D &idx,char *buf,int n) {
 collideMgr::collideMgr(const CollideGrid3d &gridMap_,
     const CProxy_collideClient &client_,
     const CProxy_collideVoxel &voxels)
-  :thisproxy(thisgroup), voxelProxy(voxels),
+  :voxelProxy(voxels),
   gridMap(gridMap_), client(client_), aggregator(gridMap,this)
 {
   steps=0;
@@ -340,6 +352,27 @@ collideMgr::collideMgr(const CollideGrid3d &gridMap_,
   collisionStarted = false;
 }
 
+collideMgr::collideMgr(CkMigrateMessage* m) :
+  CBase_collideMgr(m),
+  gridMap(CollideGrid3d(CkVector3d(0, 0, 0),CkVector3d(2, 100, 2))),
+  aggregator(gridMap,this)
+{
+  steps=0;
+  nContrib=0;
+  contribCount=0;
+  msgsSent=msgsRecvd=0;
+  totalLocalVoxels = -1;
+  collisionStarted = false;
+}
+
+// Reinitialize collideClient's state on restart
+void collideMgr::reinitClient(
+  CollisionClientFn clientFn,
+  void *clientParam )
+{
+  client.ckLocalBranch()->setClient(clientFn, clientParam);
+}
+
 //Maintain contributor registration count
 void collideMgr::registerContributor(int chunkNo)
 {
@@ -417,7 +450,8 @@ void collideMgr::tryAdvance(void)
       steps++;
       contribCount=0;
       msgsSent=msgsRecvd=0;
-      contribute(CkCallback(CkReductionTarget(collideMgr,reductionFinished), thisProxy[0]));
+      CProxy_collideMgr proxy(ckGetGroupID());
+      contribute(CkCallback(CkReductionTarget(collideMgr,reductionFinished), proxy[0]));
     }
 }
 
@@ -426,8 +460,9 @@ void collideMgr::reductionFinished(void)
 {
   CM_STATUS("collideMgr::reductionFinished");
   //Broadcast Collision start:
-  thisProxy.determineNumVoxels();
-  voxelProxy.initiateCollision(thisProxy);
+  CProxy_collideMgr proxy(ckGetGroupID());
+  proxy.determineNumVoxels();
+  voxelProxy.initiateCollision(proxy);
 }
 
 void collideMgr::checkRegistrationComplete() {
@@ -586,6 +621,10 @@ void collideVoxel::startCollision(int step,
   CC_STATUS("} startCollision");
 }
 
+collideClient::collideClient() {}
+
+collideClient::collideClient(CkMigrateMessage* m) : Group(m) {}
+
 collideClient::~collideClient() {}
 
 /********************** serialCollideClient *****************/
@@ -596,6 +635,13 @@ serialCollideClient::serialCollideClient(void) {
   useCb = false;
 }
 
+serialCollideClient::serialCollideClient(CkMigrateMessage* m) : collideClient(m)
+{
+  clientFn = NULL;
+  clientParam = NULL;
+  clientCb = CkCallback(CkCallback::ignore);
+}
+
 serialCollideClient::serialCollideClient(CkCallback clientCb_) {
   clientFn=NULL;
   clientParam=NULL;
@@ -626,8 +672,9 @@ void serialCollideClient::reductionDone(CkReductionMsg *msg)
 {
   int nColl=msg->getSize()/sizeof(Collision);
   CM_STATUS("serialCollideClient with "<<nColl<<" collisions");
-  if (clientFn!=NULL) //User wants Collisions on node 0
+  if (clientFn!=NULL) {//User wants Collisions on node 0
     (clientFn)(clientParam,nColl,(Collision *)msg->getData());
+  }
   else //FIXME: never registered a client
     CkAbort("Forgot to call serialCollideClient::setClient!\n");
   delete msg;
diff --git a/src/libs/ck-libs/collide/collidecharm.ci b/src/libs/ck-libs/collide/collidecharm.ci
index 7676bbd32a..0761c61273 100644
--- a/src/libs/ck-libs/collide/collidecharm.ci
+++ b/src/libs/ck-libs/collide/collidecharm.ci
@@ -3,7 +3,7 @@ module collidecharm {
 
   group collideClient {
   };
-  group serialCollideClient : collideClient {
+  group [migratable] serialCollideClient : collideClient {
     entry serialCollideClient();
     entry serialCollideClient(CkCallback clientCb_);
     entry void reductionDone(CkReductionMsg *m);
@@ -13,7 +13,7 @@ module collidecharm {
     entry distributedCollideClient(CkCallback clientCb_);
   };
 
-  group collideMgr {
+  group [migratable] collideMgr {
     entry collideMgr(CollideGrid3d gridMap,
         CProxy_collideClient client,
         CkArrayID cells);
diff --git a/src/libs/ck-libs/collide/collidecharm.h b/src/libs/ck-libs/collide/collidecharm.h
index cb595a95b6..09831fdeff 100644
--- a/src/libs/ck-libs/collide/collidecharm.h
+++ b/src/libs/ck-libs/collide/collidecharm.h
@@ -9,6 +9,9 @@
 #include "collide_util.h"
 #include "collidecharm.decl.h"
 
+/// This client function is called on PE 0 with a Collision list
+typedef void (*CollisionClientFn)(void *param,int nColl,Collision *colls);
+
 /********************** collideClient *****************
   A place for the assembled Collision lists to go.
   Each voxel calls this "Collisions" method with their
@@ -22,16 +25,17 @@
   */
 class collideClient : public Group {
   public:
+    collideClient();
+    collideClient(CkMigrateMessage* m);
     virtual ~collideClient();
     virtual void collisions(int step,CollisionList &colls) =0;
+    virtual void setClient(CollisionClientFn clientFn,
+        void *clientParam) = 0;
 };
 
 /********************** serialCollideClient *****************
   Reduces the Collision list down to processor 0.
   */
-/// This client function is called on PE 0 with a Collision list
-typedef void (*CollisionClientFn)(void *param,int nColl,Collision *colls);
-
 /// Call this on processor 0 to build a Collision client that
 ///  just calls this serial routine on processor 0 with the final,
 ///  complete Collision list.
@@ -47,6 +51,13 @@ CkGroupID CollideDistributedClient(CkCallback clientCb);
 /****************** Collision Interface ******************/
 typedef CkGroupID CollideHandle;
 
+/// Call this on all processors at restart to reinitialize the Collision client
+/// with the correct clientFn and clientParam.
+void CollideSerialClientRestart(
+  CollideHandle h,
+  CollisionClientFn clientFn,
+  void *clientParam );
+
 /// Create a collider group to contribute objects to.
 ///  Should be called on processor 0.
 CollideHandle CollideCreate(const CollideGrid3d &gridMap,
diff --git a/src/libs/ck-libs/collide/collidecharm_impl.h b/src/libs/ck-libs/collide/collidecharm_impl.h
index 8ea606fd39..2794f91eea 100644
--- a/src/libs/ck-libs/collide/collidecharm_impl.h
+++ b/src/libs/ck-libs/collide/collidecharm_impl.h
@@ -101,7 +101,6 @@ class CollisionAggregator {
 
 class collideMgr : public CBase_collideMgr
 {
-  CProxy_collideMgr thisproxy;
   private:
   void status(const char *msg) {
     CkPrintf("CMgr pe %d> %s\n",CkMyPe(),msg);
@@ -131,11 +130,26 @@ class collideMgr : public CBase_collideMgr
   collideMgr(const CollideGrid3d &gridMap,
       const CProxy_collideClient &client,
       const CProxy_collideVoxel &voxels);
+  collideMgr(CkMigrateMessage* m);
+
+  void pup(PUP::er &p) {
+    // The migrate constructor does not initialize Group/CkReductionMgr state.
+    // Restore it explicitly so group reductions have a valid thisProxy/tree.
+    Group::pup(p);
+    p | voxelProxy;
+    p | gridMap;
+    p | client;
+  }
 
   //Maintain contributor registration count
   void registerContributor(int chunkNo);
   void unregisterContributor(int chunkNo);
 
+  // Reinitialize collideClient's state on restart
+  void reinitClient(
+    CollisionClientFn clientFn,
+    void *clientParam );
+
   //Clients call this to contribute their objects
   void addBoxes(int chunkNo, int n, const bbox3d* boxes, const int* prio);
 
@@ -194,6 +208,13 @@ class serialCollideClient : public collideClient {
   public:
   serialCollideClient(void);
   serialCollideClient(CkCallback clientCb_);
+  serialCollideClient(CkMigrateMessage *m);
+  void pup(PUP::er &p) {
+    // The reduction callback in collisions() relies on Group/CkReductionMgr
+    // state restored by Group::pup(), including thisgroup and thisProxy.
+    Group::pup(p);
+    p | useCb;
+  }
 
   /// Call this client function on processor 0:
   void setClient(CollisionClientFn clientFn,void *clientParam);
@@ -216,6 +237,7 @@ class distributedCollideClient : public collideClient {
 
   /// Called by voxel array on each processor:
   virtual void collisions(int step,CollisionList &colls);
+  void setClient(CollisionClientFn, void *) {}
 };
 
 
diff --git a/src/libs/ck-libs/collide/threadCollide.C b/src/libs/ck-libs/collide/threadCollide.C
index 4a5c7ca321..51a94486ff 100644
--- a/src/libs/ck-libs/collide/threadCollide.C
+++ b/src/libs/ck-libs/collide/threadCollide.C
@@ -77,6 +77,9 @@ class threadCollideMgr : public CBase_threadCollideMgr
     contrib[chunkNo]=NULL;
   }
 
+  /// Placeholder for collideClient's restart reinitialization interface.
+  void setClient(CollisionClientFn, void *) {}
+
   /// collideClient interface (called by voxels)
   /// Splits up collisions by destination PE
   void collisions(int step,CollisionList &colls);