diff --git a/src/miner.cpp b/src/miner.cpp
index 16c18146b..72d6d04df 100644
--- a/src/miner.cpp
+++ b/src/miner.cpp
@@ -1102,6 +1102,14 @@ void static RandomXMiner()
             // Create new block
             unsigned int nTransactionsUpdatedLast = mempool.GetTransactionsUpdated();
             CBlockIndex* pindexPrev = chainActive.LastTip();
+
+            // If we don't have a valid chain tip to work from, wait and try again.
+            if (pindexPrev == nullptr) {
+                fprintf(stderr,"%s: null pindexPrev, trying again...\n",__func__);
+                MilliSleep(1000);
+                continue;
+            }
+
             if ( Mining_height != pindexPrev->GetHeight()+1 )
             {
                 Mining_height = pindexPrev->GetHeight()+1;
@@ -1460,6 +1468,14 @@ void static BitcoinMiner()
             //
             unsigned int nTransactionsUpdatedLast = mempool.GetTransactionsUpdated();
             CBlockIndex* pindexPrev = chainActive.LastTip();
+
+            // If we don't have a valid chain tip to work from, wait and try again.
+            if (pindexPrev == nullptr) {
+                fprintf(stderr,"%s: null pindexPrev, trying again...\n",__func__);
+                MilliSleep(1000);
+                continue;
+            }
+
             if ( Mining_height != pindexPrev->GetHeight()+1 )
             {
                 Mining_height = pindexPrev->GetHeight()+1;