diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index 2a595d4cb24..07bc742090f 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -1323,11 +1323,14 @@ void CWallet::MarkConflicted(const uint256& hashBlock, int conflicting_height, c
 {
     LOCK(cs_wallet);
 
-    int conflictconfirms = (m_last_block_processed_height - conflicting_height + 1) * -1;
     // If number of conflict confirms cannot be determined, this means
     // that the block is still unknown or not yet part of the main chain,
     // for example when loading the wallet during a reindex. Do nothing in that
     // case.
+    if (m_last_block_processed_height < 0 || conflicting_height < 0) {
+        return;
+    }
+    int conflictconfirms = (m_last_block_processed_height - conflicting_height + 1) * -1;
     if (conflictconfirms >= 0)
         return;