diff --git a/pallets/subtensor/src/migrations/migrate_fix_subnet_hotkey_lock_swaps.rs b/pallets/subtensor/src/migrations/migrate_fix_subnet_hotkey_lock_swaps.rs
index 7ff1dea7c8..93af663092 100644
--- a/pallets/subtensor/src/migrations/migrate_fix_subnet_hotkey_lock_swaps.rs
+++ b/pallets/subtensor/src/migrations/migrate_fix_subnet_hotkey_lock_swaps.rs
@@ -273,30 +273,51 @@ pub fn migrate_fix_subnet_hotkey_lock_swaps<T: Config>() -> Weight {
         };
         let netuid = NetUid::from(fix.netuid);
 
+        let index_reads: u64;
+        let index_writes: u64;
+        let lock_take_reads: u64;
+        let lock_take_writes: u64;
         let locks_to_fix: Vec<(T::AccountId, LockState)> = if let Some(coldkey) = fix.coldkey {
             let Some(coldkey) = decode_account_id32::<T>(coldkey) else {
                 log::error!("Failed to decode coldkey: {}", coldkey);
                 continue;
             };
-            Lock::<T>::take((coldkey.clone(), netuid, old_hotkey.clone()))
-                .map(|lock| vec![(coldkey, lock)])
-                .unwrap_or_default()
+            index_reads = 0;
+            index_writes = 1;
+            lock_take_reads = 1;
+            LockingColdkeys::<T>::remove((netuid, old_hotkey.clone(), coldkey.clone()));
+            if let Some(lock) = Lock::<T>::take((coldkey.clone(), netuid, old_hotkey.clone())) {
+                lock_take_writes = 1;
+                vec![(coldkey, lock)]
+            } else {
+                lock_take_writes = 0;
+                Vec::new()
+            }
         } else {
-            let locks: Vec<(T::AccountId, LockState)> = Lock::<T>::iter()
-                .filter_map(|((coldkey, lock_netuid, hotkey), lock)| {
-                    (lock_netuid == netuid && hotkey == old_hotkey).then_some((coldkey, lock))
+            let coldkeys: Vec<T::AccountId> =
+                LockingColdkeys::<T>::iter_prefix((netuid, old_hotkey.clone()))
+                    .map(|(coldkey, ())| coldkey)
+                    .collect();
+            let indexed_coldkeys = coldkeys.len() as u64;
+            index_reads = indexed_coldkeys;
+            index_writes = indexed_coldkeys;
+            lock_take_reads = indexed_coldkeys;
+
+            let locks: Vec<(T::AccountId, LockState)> = coldkeys
+                .into_iter()
+                .filter_map(|coldkey| {
+                    LockingColdkeys::<T>::remove((netuid, old_hotkey.clone(), coldkey.clone()));
+                    Lock::<T>::take((coldkey.clone(), netuid, old_hotkey.clone()))
+                        .map(|lock| (coldkey, lock))
                 })
                 .collect();
-            for (coldkey, _) in &locks {
-                Lock::<T>::remove((coldkey.clone(), netuid, old_hotkey.clone()));
-            }
+            lock_take_writes = locks.len() as u64;
             locks
         };
-        let locks_to_fix_count = locks_to_fix.len() as u64;
-        weight = weight.saturating_add(
-            T::DbWeight::get()
-                .reads_writes(locks_to_fix_count.saturating_add(1), locks_to_fix_count),
-        );
+        weight = weight.saturating_add(T::DbWeight::get().reads_writes(
+            index_reads.saturating_add(lock_take_reads),
+            index_writes.saturating_add(lock_take_writes),
+        ));
 
         if locks_to_fix.is_empty() {
             missing_locks = missing_locks.saturating_add(1);
@@ -323,7 +344,8 @@ pub fn migrate_fix_subnet_hotkey_lock_swaps<T: Config>() -> Weight {
             }
 
             Lock::<T>::insert((coldkey.clone(), netuid, new_hotkey.clone()), lock.clone());
-            weight = weight.saturating_add(T::DbWeight::get().writes(1));
+            LockingColdkeys::<T>::insert((netuid, new_hotkey.clone(), coldkey.clone()), ());
+            weight = weight.saturating_add(T::DbWeight::get().writes(2));
 
             if !new_hotkey_is_owner {
                 add_to_aggregate::<T>(&coldkey, netuid, &new_hotkey, &lock);
diff --git a/pallets/subtensor/src/tests/migration.rs b/pallets/subtensor/src/tests/migration.rs
index 73cdacac7e..84f20da888 100644
--- a/pallets/subtensor/src/tests/migration.rs
+++ b/pallets/subtensor/src/tests/migration.rs
@@ -123,14 +123,17 @@ fn test_migrate_fix_subnet_hotkey_lock_swaps_moves_or_discards_conflicts() {
             (coldkey_to_move, netuid, old_hotkey),
             moved_lock.clone(),
         );
+        LockingColdkeys::<Test>::insert((netuid, old_hotkey, coldkey_to_move), ());
         Lock::<Test>::insert(
             (coldkey_with_conflict, netuid, old_hotkey),
             discarded_lock.clone(),
         );
+        LockingColdkeys::<Test>::insert((netuid, old_hotkey, coldkey_with_conflict), ());
         Lock::<Test>::insert(
             (coldkey_with_conflict, netuid, new_hotkey),
             existing_destination_lock.clone(),
         );
+        LockingColdkeys::<Test>::insert((netuid, new_hotkey, coldkey_with_conflict), ());
         DecayingLock::<Test>::insert(coldkey_to_move, netuid, false);
         DecayingLock::<Test>::insert(coldkey_with_conflict, netuid, false);
         DecayingLock::<Test>::insert(chained_coldkey, chained_netuid, false);
@@ -148,6 +151,10 @@ fn test_migrate_fix_subnet_hotkey_lock_swaps_moves_or_discards_conflicts() {
             (chained_coldkey, chained_netuid, chained_first_hotkey),
             chained_lock.clone(),
         );
+        LockingColdkeys::<Test>::insert(
+            (chained_netuid, chained_first_hotkey, chained_coldkey),
+            (),
+        );
         HotkeyLock::<Test>::insert(chained_netuid, chained_first_hotkey, chained_lock.clone());
 
         let weight =
@@ -157,14 +164,34 @@ fn test_migrate_fix_subnet_hotkey_lock_swaps_moves_or_discards_conflicts() {
         assert!(HasMigrationRun::<Test>::get(&migration_name));
         assert!(Lock::<Test>::get((coldkey_to_move, netuid, old_hotkey)).is_none());
         assert!(Lock::<Test>::get((coldkey_with_conflict, netuid, old_hotkey)).is_none());
+        assert!(!LockingColdkeys::<Test>::contains_key((
+            netuid,
+            old_hotkey,
+            coldkey_to_move
+        )));
+        assert!(!LockingColdkeys::<Test>::contains_key((
+            netuid,
+            old_hotkey,
+            coldkey_with_conflict
+        )));
         assert_eq!(
             Lock::<Test>::get((coldkey_to_move, netuid, new_hotkey)),
             Some(moved_lock.clone())
         );
+        assert!(LockingColdkeys::<Test>::contains_key((
+            netuid,
+            new_hotkey,
+            coldkey_to_move
+        )));
         assert_eq!(
             Lock::<Test>::get((coldkey_with_conflict, netuid, new_hotkey)),
             Some(existing_destination_lock.clone())
         );
+        assert!(LockingColdkeys::<Test>::contains_key((
+            netuid,
+            new_hotkey,
+            coldkey_with_conflict
+        )));
         assert!(HotkeyLock::<Test>::get(netuid, old_hotkey).is_none());
 
         let new_aggregate = HotkeyLock::<Test>::get(netuid, new_hotkey)
@@ -193,10 +220,25 @@ fn test_migrate_fix_subnet_hotkey_lock_swaps_moves_or_discards_conflicts() {
             chained_middle_hotkey
         ))
         .is_none());
+        assert!(!LockingColdkeys::<Test>::contains_key((
+            chained_netuid,
+            chained_first_hotkey,
+            chained_coldkey
+        )));
+        assert!(!LockingColdkeys::<Test>::contains_key((
+            chained_netuid,
+            chained_middle_hotkey,
+            chained_coldkey
+        )));
         assert_eq!(
             Lock::<Test>::get((chained_coldkey, chained_netuid, chained_final_hotkey)),
             Some(chained_lock.clone())
         );
+        assert!(LockingColdkeys::<Test>::contains_key((
+            chained_netuid,
+            chained_final_hotkey,
+            chained_coldkey
+        )));
         assert!(HotkeyLock::<Test>::get(chained_netuid, chained_first_hotkey).is_none());
         assert!(HotkeyLock::<Test>::get(chained_netuid, chained_middle_hotkey).is_none());
         assert_eq!(
diff --git a/pallets/subtensor/src/tests/swap_hotkey_with_subnet.rs b/pallets/subtensor/src/tests/swap_hotkey_with_subnet.rs
index 1e200aaedd..beb8ec9a75 100644
--- a/pallets/subtensor/src/tests/swap_hotkey_with_subnet.rs
+++ b/pallets/subtensor/src/tests/swap_hotkey_with_subnet.rs
@@ -900,22 +900,23 @@ fn test_swap_owner_old_hotkey_not_exist() {
     });
 }
 
-// SKIP_WASM_BUILD=1 RUST_LOG=debug cargo test --test swap_hotkey_with_subnet -- test_swap_owner_new_hotkey_already_exists --exact --nocapture
+// SKIP_WASM_BUILD=1 cargo test --package pallet-subtensor --lib -- tests::swap_hotkey_with_subnet::test_swap_owner_new_hotkey_already_exists --exact --nocapture
 #[test]
 fn test_swap_owner_new_hotkey_already_exists() {
     new_test_ext(1).execute_with(|| {
         let old_hotkey = U256::from(1);
         let new_hotkey = U256::from(2);
         let coldkey = U256::from(3);
+        let another_coldkey = U256::from(4);
 
-        let netuid = add_dynamic_network(&new_hotkey, &coldkey);
+        let netuid = add_dynamic_network(&old_hotkey, &coldkey);
         add_balance_to_coldkey_account(&coldkey, 1_000_000_000_000_u64.into());
 
         // old_hotkey is owned by coldkey; new_hotkey was already registered on `netuid`
         // by add_dynamic_network (the condition under test). Do NOT reassign new_hotkey to
         // a foreign coldkey — the new_hotkey-ownership check (NonAssociatedColdKey) would
         // then fire before the already-registered-in-subnet check this test targets.
-        Owner::<Test>::insert(old_hotkey, coldkey);
+        Owner::<Test>::insert(new_hotkey, another_coldkey);
 
         // Perform the swap
         System::set_block_number(System::block_number() + HotkeySwapOnSubnetInterval::get());
@@ -927,7 +928,7 @@ fn test_swap_owner_new_hotkey_already_exists() {
                 Some(netuid),
                 false
             ),
-            Error::<Test>::HotKeyAlreadyRegisteredInSubNet
+            Error::<Test>::NonAssociatedColdKey
         );
 
         // Verify the swap
diff --git a/runtime/src/lib.rs b/runtime/src/lib.rs
index 5cf4d7aadb..94e25a46fb 100644
--- a/runtime/src/lib.rs
+++ b/runtime/src/lib.rs
@@ -234,7 +234,7 @@ pub const VERSION: RuntimeVersion = RuntimeVersion {
     //   `spec_version`, and `authoring_version` are the same between Wasm and native.
     // This value is set to 100 to notify Polkadot-JS App (https://polkadot.js.org/apps) to use
     //   the compatible custom types.
-    spec_version: 419,
+    spec_version: 420,
     impl_version: 1,
     apis: RUNTIME_API_VERSIONS,
     transaction_version: 1,