diff --git a/src/komodo_bitcoind.h b/src/komodo_bitcoind.h
index 9c615c329..bfd138287 100644
--- a/src/komodo_bitcoind.h
+++ b/src/komodo_bitcoind.h
@@ -605,7 +605,7 @@ CBlockIndex *komodo_chainactive(int32_t height)
 uint32_t komodo_heightstamp(int32_t height)
 {
     CBlock block; CBlockIndex *ptr;
-    if ( (ptr= komodo_chainactive(height)) != 0 )
+    if ( height > 0 && (ptr= komodo_chainactive(height)) != 0 )
     {
         if ( komodo_blockload(block,ptr) == 0 && komodo_block2height(&block) == height )
             return(block.nTime);
diff --git a/src/main.cpp b/src/main.cpp
index 4c37892bd..de593507f 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -761,6 +761,8 @@ int32_t komodo_validate_interest(uint32_t *expiredp,const CTransaction& tx,int32
                 } else fprintf(stderr,"validateinterest grandfather.%d locktime %u vs txheighttime.%u tiptime.%u txb.%u cmp.%u\n",(int32_t)txheight,tx.nLockTime,txheighttime,tiptime,txblocktime,cmptime);
             }
         }*/
+        if ( txheightarg == 0 )
+            txheightarg = chainActive.Tip()->nHeight + 1;
         if ( (cmptime= komodo_heightstamp(txheightarg-1)) == 0 )
         {
             cmptime = chainActive.Tip()->nTime;