diff --git a/src/main.cpp b/src/main.cpp
index 261694762..228f0abcb 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -2887,17 +2887,17 @@ static bool ActivateBestChainStep(CValidationState &state, CBlockIndex *pindexMo
     }
     if ( KOMODO_REWIND != 0 )
     {
-        fprintf(stderr,"rewind ht.%d\n",chainActive.Tip()->nHeight);
+        fprintf(stderr,"rewind start ht.%d\n",chainActive.Tip()->nHeight);
         while ( chainActive.Tip()->nHeight > KOMODO_REWIND )
         {
             if ( !DisconnectTip(state) )
             {
                 InvalidateBlock(state,chainActive.Tip());
-                return false;
+                break;
             }
         }
         fprintf(stderr,"reached rewind.%d, best to do: ./komodo-cli stop\n",KOMODO_REWIND);
-        sleep(60);
+        sleep(3600);
         KOMODO_REWIND = 0;
         return(true);
     }
@@ -3331,7 +3331,7 @@ bool CheckBlock(int32_t height,CBlockIndex *pindex,const CBlock& block, CValidat
     BOOST_FOREACH(const CTransaction& tx, block.vtx)
     {
         uint32_t prevtime = 0; CBlockIndex *ptr;
-        if ( height == chainActive.Tip()->nHeight+1 )
+        if ( chainActive.Tip() != 0 && height == chainActive.Tip()->nHeight+1 )
             prevtime = chainActive.Tip()->nTime;
         else if ( pindex != 0 )
         {
@@ -3340,7 +3340,7 @@ bool CheckBlock(int32_t height,CBlockIndex *pindex,const CBlock& block, CValidat
         }
         if ( prevtime == 0 )
         {
-            if ( height > 0 && (ptr= chainActive[height-1]) )
+            if ( height > 0 && (ptr= chainActive[height-1]) != 0 )
                 prevtime = ptr->nTime;
         }
         if ( komodo_validate_interest(0,tx,height,prevtime) < 0 )