diff --git a/libretroshare/src/gxs/rsgds.h b/libretroshare/src/gxs/rsgds.h
index 0593610ce..c56b47c12 100644
--- a/libretroshare/src/gxs/rsgds.h
+++ b/libretroshare/src/gxs/rsgds.h
@@ -90,6 +90,8 @@ public:
 
     uint32_t mSuppliers ;
     uint32_t mMaxVisibleCount ;
+    bool     mGrpAutoSync ;
+    bool     mAllowMsgSync;
 };
 
 typedef std::map<RsGxsGroupId,      std::vector<RsNxsMsg*> > NxsMsgDataResult;
diff --git a/libretroshare/src/gxs/rsgenexchange.cc b/libretroshare/src/gxs/rsgenexchange.cc
index 9c484b79e..3396b1e94 100644
--- a/libretroshare/src/gxs/rsgenexchange.cc
+++ b/libretroshare/src/gxs/rsgenexchange.cc
@@ -81,7 +81,7 @@ RsGenExchange::RsGenExchange(RsGeneralDataService *gds, RsNetworkExchangeService
   mLastClean((int)time(NULL) - (int)(RSRandom::random_u32() % MSG_CLEANUP_PERIOD)),	// this helps unsynchronising the checks for the different services
   mMsgCleanUp(NULL),
   mChecking(false),
-  mLastCheck((int)time(NULL) - (int)(RSRandom::random_u32() % INTEGRITY_CHECK_PERIOD)),	// this helps unsynchronising the checks for the different services
+  mLastCheck((int)time(NULL) - (int)(RSRandom::random_u32() % INTEGRITY_CHECK_PERIOD) + 120),	// this helps unsynchronising the checks for the different services, with 2 min security to avoid checking right away before statistics come up.
   mIntegrityCheck(NULL),
   CREATE_FAIL(0),
   CREATE_SUCCESS(1),
@@ -211,6 +211,11 @@ void RsGenExchange::tick()
                                         	std::cerr << "    " << *it << std::endl;
 #endif
 					mNotifications.push_back(gc);
+
+                    // also notify the network exchange service that these groups no longer exist.
+
+                    if(mNetService)
+                        mNetService->removeGroups(grpIds) ;
 				}
 
 				if (!msgIds.empty()) {
@@ -1639,6 +1644,11 @@ uint32_t RsGenExchange::getSyncPeriod(const RsGxsGroupId& grpId)
         return RS_GXS_DEFAULT_MSG_REQ_PERIOD;
 }
 
+bool     RsGenExchange::getGroupNetworkStats(const RsGxsGroupId& grpId,RsGroupNetworkStats& stats)
+{
+	return (!mNetService) || mNetService->getGroupNetworkStats(grpId,stats) ;
+}
+
 void     RsGenExchange::setSyncPeriod(const RsGxsGroupId& grpId,uint32_t age_in_secs)
 {
 	if(mNetService != NULL)
diff --git a/libretroshare/src/gxs/rsgenexchange.h b/libretroshare/src/gxs/rsgenexchange.h
index 706ed9401..959faeda6 100644
--- a/libretroshare/src/gxs/rsgenexchange.h
+++ b/libretroshare/src/gxs/rsgenexchange.h
@@ -646,6 +646,7 @@ public:
     virtual uint32_t getDefaultSyncPeriod();
     virtual uint32_t getSyncPeriod(const RsGxsGroupId& grpId) ;
     virtual void     setSyncPeriod(const RsGxsGroupId& grpId,uint32_t age_in_secs) ;
+	virtual bool     getGroupNetworkStats(const RsGxsGroupId& grpId,RsGroupNetworkStats& stats);
 
     uint16_t serviceType() const { return mServType ; }
     uint32_t serviceFullType() const { return ((uint32_t)mServType << 8) + (((uint32_t) RS_PKT_VERSION_SERVICE) << 24); }
diff --git a/libretroshare/src/gxs/rsgxsnetservice.cc b/libretroshare/src/gxs/rsgxsnetservice.cc
index 7653c4e20..51d8e3d04 100644
--- a/libretroshare/src/gxs/rsgxsnetservice.cc
+++ b/libretroshare/src/gxs/rsgxsnetservice.cc
@@ -225,12 +225,12 @@
  	NXS_NET_DEBUG_7		encryption/decryption of transactions
 
  ***/
-//#define NXS_NET_DEBUG_0 	1
+#define NXS_NET_DEBUG_0 	1
 //#define NXS_NET_DEBUG_1 	1
 //#define NXS_NET_DEBUG_2 	1
 //#define NXS_NET_DEBUG_3 	1
 //#define NXS_NET_DEBUG_4 	1
-//#define NXS_NET_DEBUG_5 	1
+#define NXS_NET_DEBUG_5 	1
 //#define NXS_NET_DEBUG_6 	1
 //#define NXS_NET_DEBUG_7 	1
 
@@ -2311,6 +2311,8 @@ bool RsGxsNetService::getGroupNetworkStats(const RsGxsGroupId& gid,RsGroupNetwor
 
     stats.mSuppliers = it->second.suppliers.ids.size();
     stats.mMaxVisibleCount = it->second.max_visible_count ;
+    stats.mAllowMsgSync = mAllowMsgSync ;
+    stats.mGrpAutoSync = mGrpAutoSync ;
 
     return true ;
 }
@@ -4046,7 +4048,12 @@ void RsGxsNetService::handleRecvSyncMessage(RsNxsSyncMsgReqItem *item,bool item_
     GXSNETDEBUG_PG(item->PeerId(),item->grpId) << "handleRecvSyncMsg(): Received last update TS of group " << item->grpId << ", for peer " << peer << ", TS = " << time(NULL) - item->updateTS << " secs ago." ;
 #endif
 
-    if(grp_is_known)
+    // We update suppliers in two cases:
+    // Case 1: the grp is known because it is the hash of an existing group, but it's not yet in the server config map
+    // Case 2: the gtp is not known, possibly because it was deleted, but there's an entry in mServerGrpConfigMap due to statistics gathering. Still, statistics are only
+    // 		 gathered from known suppliers. So statistics never add new suppliers. These are only added here.
+
+    if(grp_is_known || mServerGrpConfigMap.find(item->grpId)!=mServerGrpConfigMap.end())
     {
 	    RsGxsGrpConfig & rec(mServerGrpConfigMap[item->grpId]) ;	// this creates it if needed. When the grp is unknown (and hashed) this will would create a unused entry
 	    rec.suppliers.ids.insert(peer) ;
@@ -4725,7 +4732,7 @@ void RsGxsNetService::handleRecvPublishKeys(RsNxsGroupPublishKeyItem *item)
 
 	if(ret)
 	{
-#ifdef NXS_NET_DEBUG
+#ifdef NXS_NET_DEBUG_3
 		GXSNETDEBUG_PG(item->PeerId(),item->grpId)<< "  updated database with new publish keys." << std::endl;
 #endif
         mNewPublishKeysToNotify.insert(item->grpId) ;
@@ -4752,6 +4759,39 @@ bool RsGxsNetService::getGroupServerUpdateTS(const RsGxsGroupId& gid,time_t& gro
     return true ;
 }
 
+bool RsGxsNetService::removeGroups(const std::list<RsGxsGroupId>& groups)
+{
+    RS_STACK_MUTEX(mNxsMutex) ;
+
+	GXSNETDEBUG___ << "Removing group information from deleted groups:" << std::endl;
+
+    for(std::list<RsGxsGroupId>::const_iterator git(groups.begin());git!=groups.end();++git)
+    {
+		GXSNETDEBUG__G(*git) << "  deleting info for group " << *git << std::endl;
+
+        GrpConfigMap::iterator it = mServerGrpConfigMap.find(*git) ;
+
+        if(it != mServerGrpConfigMap.end())
+        {
+            it->second.suppliers.TlvClear();			// we dont erase the entry, because we want to keep the user-defined sync parameters.
+            it->second.max_visible_count = 0;
+        }
+
+        mServerMsgUpdateMap.erase(*git) ;
+
+        for(ClientMsgMap::iterator it(mClientMsgUpdateMap.begin());it!=mClientMsgUpdateMap.end();++it)
+            it->second.msgUpdateInfos.erase(*git) ;
+
+        // This last step is very important: it makes RS re-sync all groups after deleting, with every new peer. If may happen indeed that groups
+        // are deleted because there's no suppliers since the actual supplier friend is offline for too long. In this case, the group needs
+        // to re-appear when the friend who is a subscriber comes online again.
+
+        mClientGrpUpdateMap.clear();
+    }
+
+	IndicateConfigChanged();
+}
+
 bool RsGxsNetService::stampMsgServerUpdateTS(const RsGxsGroupId& gid)
 {
     RS_STACK_MUTEX(mNxsMutex) ;
diff --git a/libretroshare/src/gxs/rsgxsnetservice.h b/libretroshare/src/gxs/rsgxsnetservice.h
index 6aae36462..b14d55058 100644
--- a/libretroshare/src/gxs/rsgxsnetservice.h
+++ b/libretroshare/src/gxs/rsgxsnetservice.h
@@ -161,6 +161,7 @@ public:
     
     virtual bool getGroupServerUpdateTS(const RsGxsGroupId& gid,time_t& grp_server_update_TS,time_t& msg_server_update_TS) ;
     virtual bool stampMsgServerUpdateTS(const RsGxsGroupId& gid) ;
+    virtual bool removeGroups(const std::list<RsGxsGroupId>& groups);
 
     /* p3Config methods */
 public:
diff --git a/libretroshare/src/gxs/rsgxsutil.cc b/libretroshare/src/gxs/rsgxsutil.cc
index aa5c5558a..2e9ce5204 100644
--- a/libretroshare/src/gxs/rsgxsutil.cc
+++ b/libretroshare/src/gxs/rsgxsutil.cc
@@ -188,20 +188,17 @@ bool RsGxsIntegrityCheck::check()
 		    grpsToDel.push_back(grp->grpId);
 	    }
 
-#ifdef TODO
-		if(!(grp->metaData->mSubscribeFlags & GXS_SERV::GROUP_SUBSCRIBE_SUBSCRIBED))
+		if(!(grp->metaData->mSubscribeFlags & GXS_SERV::GROUP_SUBSCRIBE_SUBSCRIBED) && !(grp->metaData->mSubscribeFlags & GXS_SERV::GROUP_SUBSCRIBE_ADMIN) && !(grp->metaData->mSubscribeFlags & GXS_SERV::GROUP_SUBSCRIBE_PUBLISH))
         {
             RsGroupNetworkStats stats ;
             mGenExchangeClient->getGroupNetworkStats(grp->grpId,stats);
 
-            if(stats.mSuppliers == 0 && stats.mMaxVisibleCount == 0)
+            if(stats.mSuppliers == 0 && stats.mMaxVisibleCount == 0 && stats.mGrpAutoSync)
             {
-                GXSUTIL_DEBUG() << "Scheduling group \"" << grp->metaData->mGroupName << "\" ID=" << grp->grpId << " for deletion because it has no suppliers not any visible data at friends." << std::endl;
-#warning Should we do that here? What happens for groups that are normally empty such as identities?
+                GXSUTIL_DEBUG() << "Scheduling group \"" << grp->metaData->mGroupName << "\" ID=" << grp->grpId << " in service " << std::hex << mGenExchangeClient->serviceType() << std::dec << " for deletion because it has no suppliers not any visible data at friends." << std::endl;
 				grpsToDel.push_back(grp->grpId);
             }
         }
-#endif
 
 	    delete grp;
     }
diff --git a/libretroshare/src/gxs/rsnxs.h b/libretroshare/src/gxs/rsnxs.h
index 9b879d2d0..ef86caa28 100644
--- a/libretroshare/src/gxs/rsnxs.h
+++ b/libretroshare/src/gxs/rsnxs.h
@@ -162,6 +162,14 @@ public:
      */
     virtual bool stampMsgServerUpdateTS(const RsGxsGroupId& gid) =0;
 
+    /*!
+     * \brief removeGroups
+     * 			Removes time stamp information from the list of groups. This allows to re-sync them if suppliers are present.
+     * \param groups		list of groups to remove from the update maps
+     * \return 				true if nothing bad happens.
+     */
+    virtual bool removeGroups(const std::list<RsGxsGroupId>& groups)=0;
+
     /*!
      * \brief minReputationForForwardingMessages
      * 				Encodes the policy for sending/requesting messages depending on anti-spam settings.