diff --git a/src/wallet/test/wallet_tests.cpp b/src/wallet/test/wallet_tests.cpp
--- a/src/wallet/test/wallet_tests.cpp
+++ b/src/wallet/test/wallet_tests.cpp
@@ -31,9 +31,7 @@
     wallet.AddKeyPubKey(key, key.GetPubKey());
 }
 
-// Note: when backporting PR14957, see PR15321 and ensure both LockAnnotations
-// are in place.
-BOOST_FIXTURE_TEST_CASE(rescan, TestChain100Setup) {
+BOOST_FIXTURE_TEST_CASE(scan_for_wallet_transactions, TestChain100Setup) {
     auto chain = interfaces::MakeChain();
 
     // Cap last block file size, and mine new block in a new block file.
@@ -46,6 +44,24 @@
     LockAnnotation lock(::cs_main);
     auto locked_chain = chain->lock();
 
+    // Verify ScanForWalletTransactions accommodates a null start block.
+    {
+        CWallet wallet(Params(), *chain, WalletLocation(),
+                       WalletDatabase::CreateDummy());
+        AddKey(wallet, coinbaseKey);
+        WalletRescanReserver reserver(&wallet);
+        reserver.reserve();
+        const CBlockIndex *stop_block = null_block + 1,
+                          *failed_block = null_block + 1;
+        BOOST_CHECK_EQUAL(
+            wallet.ScanForWalletTransactions(nullptr, nullptr, reserver,
+                                             failed_block, stop_block),
+            CWallet::ScanResult::SUCCESS);
+        BOOST_CHECK_EQUAL(failed_block, null_block);
+        BOOST_CHECK_EQUAL(stop_block, null_block);
+        BOOST_CHECK_EQUAL(wallet.GetImmatureBalance(), Amount::zero());
+    }
+
     // Verify ScanForWalletTransactions picks up transactions in both the old
     // and new block files.
     {
@@ -54,7 +70,8 @@
         AddKey(wallet, coinbaseKey);
         WalletRescanReserver reserver(&wallet);
         reserver.reserve();
-        const CBlockIndex *stop_block, *failed_block;
+        const CBlockIndex *stop_block = null_block + 1,
+                          *failed_block = null_block + 1;
         BOOST_CHECK_EQUAL(
             wallet.ScanForWalletTransactions(oldTip, nullptr, reserver,
                                              failed_block, stop_block),
@@ -76,7 +93,8 @@
         AddKey(wallet, coinbaseKey);
         WalletRescanReserver reserver(&wallet);
         reserver.reserve();
-        const CBlockIndex *stop_block, *failed_block;
+        const CBlockIndex *stop_block = null_block + 1,
+                          *failed_block = null_block + 1;
         BOOST_CHECK_EQUAL(
             wallet.ScanForWalletTransactions(oldTip, nullptr, reserver,
                                              failed_block, stop_block),
@@ -86,6 +104,45 @@
         BOOST_CHECK_EQUAL(wallet.GetImmatureBalance(), 50 * COIN);
     }
 
+    // Prune the remaining block file.
+    PruneOneBlockFile(newTip->GetBlockPos().nFile);
+    UnlinkPrunedFiles({newTip->GetBlockPos().nFile});
+
+    // Verify ScanForWalletTransactions scans no blocks.
+    {
+        CWallet wallet(Params(), *chain, WalletLocation(),
+                       WalletDatabase::CreateDummy());
+        AddKey(wallet, coinbaseKey);
+        WalletRescanReserver reserver(&wallet);
+        reserver.reserve();
+        const CBlockIndex *stop_block = null_block + 1,
+                          *failed_block = null_block + 1;
+        BOOST_CHECK_EQUAL(
+            wallet.ScanForWalletTransactions(oldTip, nullptr, reserver,
+                                             failed_block, stop_block),
+            CWallet::ScanResult::FAILURE);
+        BOOST_CHECK_EQUAL(failed_block, newTip);
+        BOOST_CHECK_EQUAL(stop_block, null_block);
+        BOOST_CHECK_EQUAL(wallet.GetImmatureBalance(), Amount::zero());
+    }
+}
+
+BOOST_FIXTURE_TEST_CASE(importmulti_rescan, TestChain100Setup) {
+    auto chain = interfaces::MakeChain();
+
+    // Cap last block file size, and mine new block in a new block file.
+    CBlockIndex *oldTip = ::ChainActive().Tip();
+    GetBlockFileInfo(oldTip->GetBlockPos().nFile)->nSize = MAX_BLOCKFILE_SIZE;
+    CreateAndProcessBlock({}, GetScriptForRawPubKey(coinbaseKey.GetPubKey()));
+    CBlockIndex *newTip = ::ChainActive().Tip();
+
+    LockAnnotation lock(::cs_main);
+    auto locked_chain = chain->lock();
+
+    // Prune the older block file.
+    PruneOneBlockFile(oldTip->GetBlockPos().nFile);
+    UnlinkPrunedFiles({oldTip->GetBlockPos().nFile});
+
     // Verify importmulti RPC returns failure for a key whose creation time is
     // before the missing block, and success for a key whose creation time is
     // after.
@@ -321,7 +378,8 @@
         WalletRescanReserver reserver(wallet.get());
         reserver.reserve();
         const CBlockIndex *const null_block = nullptr;
-        const CBlockIndex *stop_block, *failed_block;
+        const CBlockIndex *stop_block = null_block + 1,
+                          *failed_block = null_block + 1;
         BOOST_CHECK_EQUAL(wallet->ScanForWalletTransactions(
                               ChainActive().Genesis(), nullptr, reserver,
                               failed_block, stop_block),
diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -1847,6 +1847,7 @@
 
     const CBlockIndex *pindex = pindexStart;
     failed_block = nullptr;
+    stop_block = nullptr;
 
     if (pindex) {
         WalletLogPrintf("Rescan started from block %d...\n", pindex->nHeight);