diff --git a/stores/chain_test.go b/stores/chain_test.go
index 615e27098..08b959ca9 100644
--- a/stores/chain_test.go
+++ b/stores/chain_test.go
@@ -3,6 +3,7 @@ package stores
 import (
 	"context"
 	"errors"
+	"fmt"
 	"strings"
 	"testing"
 	"time"
@@ -31,7 +32,7 @@ func TestProcessChainUpdate(t *testing.T) {
 	}
 	fcid := fcids[0]
 
-	// assert contract state returns the correct state
+	// check current contract state
 	var state api.ContractState
 	if err := ss.ProcessChainUpdate(context.Background(), func(tx sql.ChainUpdateTx) (err error) {
 		state, err = tx.ContractState(fcid)
@@ -49,22 +50,14 @@ func TestProcessChainUpdate(t *testing.T) {
 		t.Fatalf("unexpected height %v", curr.Height)
 	}
 
-	// assert update chain index is successful
+	// run chain update
 	if err := ss.ProcessChainUpdate(context.Background(), func(tx sql.ChainUpdateTx) error {
-		return tx.UpdateChainIndex(types.ChainIndex{Height: 1})
-	}); err != nil {
-		t.Fatal("unexpected error", err)
-	}
-
-	// check updated index
-	if curr, err := ss.ChainIndex(context.Background()); err != nil {
-		t.Fatal(err)
-	} else if curr.Height != 1 {
-		t.Fatalf("unexpected height %v", curr.Height)
-	}
+		// update chain index
+		if err := tx.UpdateChainIndex(types.ChainIndex{Height: 1}); err != nil {
+			return err
+		}
 
-	// assert update contract is successful
-	if err := ss.ProcessChainUpdate(context.Background(), func(tx sql.ChainUpdateTx) error {
+		// update contract
 		if err := tx.UpdateContract(fcid, 1, 2, 3); err != nil {
 			return err
 		} else if err := tx.UpdateContractState(fcid, api.ContractStateActive); err != nil {
@@ -78,7 +71,14 @@ func TestProcessChainUpdate(t *testing.T) {
 		t.Fatal("unexpected error", err)
 	}
 
-	// assert contract was updated successfully
+	// assert updated index
+	if curr, err := ss.ChainIndex(context.Background()); err != nil {
+		t.Fatal(err)
+	} else if curr.Height != 1 {
+		t.Fatalf("unexpected height %v", curr.Height)
+	}
+
+	// assert updated contract
 	var we uint64
 	if c, err := ss.Contract(context.Background(), fcid); err != nil {
 		t.Fatal("unexpected error", err)
@@ -210,31 +210,41 @@ func TestProcessChainUpdate(t *testing.T) {
 		panic("oh no")
 	}
 
+	// assert we can revert spent outputs
+	now := time.Now().Round(time.Millisecond)
+	var ses []types.StateElement
 	if err := ss.ProcessChainUpdate(context.Background(), func(tx sql.ChainUpdateTx) error {
 		index3 := types.ChainIndex{Height: 3}
 		index4 := types.ChainIndex{Height: 4}
 		created := []types.SiacoinElement{
 			{
-				StateElement:   types.StateElement{},
-				SiacoinOutput:  types.SiacoinOutput{},
+				StateElement: types.StateElement{
+					ID:          types.Hash256{1},
+					LeafIndex:   1,
+					MerkleProof: []types.Hash256{{1}, {2}},
+				},
+				SiacoinOutput: types.SiacoinOutput{
+					Address: types.Address{1},
+					Value:   types.NewCurrency64(1),
+				},
 				MaturityHeight: 100,
 			},
 		}
-		events := []wallet.Event{
-			{
-				Type: wallet.EventTypeV2Transaction,
-				Data: wallet.EventV2Transaction{},
-			},
+
+		// try spending non-existent output
+		err = tx.WalletApplyIndex(index4, nil, created, nil, time.Now())
+		if !errors.Is(err, sql.ErrOutputNotFound) {
+			return fmt.Errorf("expected ErrOutputNotFound, instead got: %w", err)
 		}
 
-		// create some elements
-		err := tx.WalletApplyIndex(index3, created, nil, events, time.Now())
+		// create the elements
+		err = tx.WalletApplyIndex(index3, created, nil, nil, time.Now())
 		if err != nil {
 			return err
 		}
 
 		// spend them
-		err = tx.WalletApplyIndex(index4, nil, created, events, time.Now())
+		err = tx.WalletApplyIndex(index4, nil, created, nil, time.Now())
 		if err != nil {
 			return err
 		}
@@ -250,8 +260,109 @@ func TestProcessChainUpdate(t *testing.T) {
 		if err != nil {
 			return err
 		}
-		return nil
+
+		// prepare event
+		events := []wallet.Event{
+			{
+				ID:        types.Hash256{1},
+				Index:     types.ChainIndex{Height: 5},
+				Type:      wallet.EventTypeV2Transaction,
+				Data:      wallet.EventV2Transaction{},
+				Timestamp: now,
+			},
+		}
+
+		// add them
+		err = tx.WalletApplyIndex(types.ChainIndex{Height: 5}, nil, nil, events, time.Now())
+		if err != nil {
+			return err
+		}
+
+		// fetch elements
+		ses, err = tx.WalletStateElements()
+		return err
+	}); err != nil {
+		t.Fatal("unexpected error", err)
+	}
+
+	// assert wallet state elements
+	if len(ses) != 1 {
+		t.Fatal("unexpected number of state elements", len(ses))
+	} else if se := ses[0]; se.ID != (types.Hash256{1}) {
+		t.Fatal("unexpected state element id", se.ID)
+	} else if se.LeafIndex != 1 {
+		t.Fatal("unexpected state element leaf index", se.LeafIndex)
+	} else if len(se.MerkleProof) != 2 {
+		t.Fatal("unexpected state element merkle proof", len(se.MerkleProof))
+	} else if se.MerkleProof[0] != (types.Hash256{1}) {
+		t.Fatal("unexpected state element merkle proof[0]", se.MerkleProof[0])
+	} else if se.MerkleProof[1] != (types.Hash256{2}) {
+		t.Fatal("unexpected state element merkle proof[1]", se.MerkleProof[1])
+	}
+
+	// update state elements
+	if err := ss.ProcessChainUpdate(context.Background(), func(tx sql.ChainUpdateTx) error {
+		ses[0].LeafIndex = 2
+		ses[0].MerkleProof = []types.Hash256{{3}, {4}}
+		err := tx.UpdateWalletStateElements(ses)
+		if err != nil {
+			return err
+		}
+
+		ses, err = tx.WalletStateElements()
+		return err
 	}); err != nil {
 		t.Fatal("unexpected error", err)
 	}
+
+	// assert wallet state elements
+	if len(ses) != 1 {
+		t.Fatal("unexpected number of state elements", len(ses))
+	} else if se := ses[0]; se.LeafIndex != 2 {
+		t.Fatal("unexpected state element leaf index", se.LeafIndex)
+	} else if len(se.MerkleProof) != 2 {
+		t.Fatal("unexpected state element merkle proof length", len(se.MerkleProof))
+	} else if se.MerkleProof[0] != (types.Hash256{3}) {
+		t.Fatal("unexpected state element merkle proof[0]", se.MerkleProof[0])
+	} else if se.MerkleProof[1] != (types.Hash256{4}) {
+		t.Fatal("unexpected state element merkle proof[1]", se.MerkleProof[1])
+	}
+
+	// assert events
+	events, err := ss.WalletEvents(0, -1)
+	if err != nil {
+		t.Fatal(err)
+	} else if len(events) != 1 {
+		t.Fatal("unexpected number of events", len(events))
+	} else if events[0].Index.Height != 5 {
+		t.Fatal("unexpected event index height", events[0].Index.Height, events[0])
+	} else if events[0].Timestamp != now {
+		t.Fatal("unexpected event timestamp", events[0].Timestamp, now)
+	}
+
+	// revert the index and assert the event got removed
+	if err := ss.ProcessChainUpdate(context.Background(), func(tx sql.ChainUpdateTx) error {
+		return tx.WalletRevertIndex(types.ChainIndex{Height: 5}, nil, nil, time.Now())
+	}); err != nil {
+		t.Fatal("expected error")
+	}
+	events, err = ss.WalletEvents(0, -1)
+	if err != nil {
+		t.Fatal(err)
+	} else if len(events) != 0 {
+		t.Fatal("unexpected number of events", len(events))
+	}
+
+	// assert we can't delete non-existing outputs when reverting
+	if err := ss.ProcessChainUpdate(context.Background(), func(tx sql.ChainUpdateTx) error {
+		return tx.WalletRevertIndex(types.ChainIndex{Height: 5}, []types.SiacoinElement{
+			{
+				StateElement:   types.StateElement{ID: types.Hash256{2}},
+				SiacoinOutput:  types.SiacoinOutput{},
+				MaturityHeight: 100,
+			},
+		}, nil, time.Now())
+	}); !errors.Is(err, sql.ErrOutputNotFound) {
+		t.Fatal("expected ErrOutputNotFound", err)
+	}
 }
diff --git a/stores/sql/chain.go b/stores/sql/chain.go
index c9c991d4e..625ce5d7e 100644
--- a/stores/sql/chain.go
+++ b/stores/sql/chain.go
@@ -12,6 +12,10 @@ import (
 	"go.uber.org/zap"
 )
 
+var (
+	ErrOutputNotFound = errors.New("output not found")
+)
+
 var contractTables = []string{
 	"contracts",
 	"archived_contracts",
diff --git a/stores/sql/mysql/chain.go b/stores/sql/mysql/chain.go
index 4e5720c9e..73cd05482 100644
--- a/stores/sql/mysql/chain.go
+++ b/stores/sql/mysql/chain.go
@@ -46,7 +46,7 @@ func (c chainUpdateTx) WalletApplyIndex(index types.ChainIndex, created, spent [
 			} else if n, err := res.RowsAffected(); err != nil {
 				return fmt.Errorf("failed to get rows affected: %w", err)
 			} else if n != 1 {
-				return fmt.Errorf("failed to delete spent output: no rows affected")
+				return fmt.Errorf("failed to delete spent output: %w", ssql.ErrOutputNotFound)
 			}
 		}
 	}
@@ -134,7 +134,7 @@ func (c chainUpdateTx) WalletRevertIndex(index types.ChainIndex, removed, unspen
 			} else if n, err := res.RowsAffected(); err != nil {
 				return fmt.Errorf("failed to get rows affected: %w", err)
 			} else if n != 1 {
-				return fmt.Errorf("failed to delete removed output: no rows affected")
+				return fmt.Errorf("failed to delete removed output: %w", ssql.ErrOutputNotFound)
 			}
 		}
 	}
diff --git a/stores/sql/sqlite/chain.go b/stores/sql/sqlite/chain.go
index 0ec937b73..95d16434c 100644
--- a/stores/sql/sqlite/chain.go
+++ b/stores/sql/sqlite/chain.go
@@ -49,7 +49,7 @@ func (c chainUpdateTx) WalletApplyIndex(index types.ChainIndex, created, spent [
 			} else if n, err := res.RowsAffected(); err != nil {
 				return fmt.Errorf("failed to get rows affected: %w", err)
 			} else if n != 1 {
-				return fmt.Errorf("failed to delete spent output: no rows affected")
+				return fmt.Errorf("failed to delete spent output: %w", ssql.ErrOutputNotFound)
 			}
 		}
 	}
@@ -89,6 +89,12 @@ func (c chainUpdateTx) WalletApplyIndex(index types.ChainIndex, created, spent [
 
 		// insert new events
 		for _, e := range events {
+			if e.Index != index {
+				return fmt.Errorf("event index %v doesn't match index being applied %v", e.Index, index)
+			} else if e.ID == (types.Hash256{}) {
+				return fmt.Errorf("event id is required")
+			}
+
 			c.l.Debugw(fmt.Sprintf("create event %v", e.ID), "height", index.Height, "block_id", index.ID)
 			data, err := json.Marshal(e.Data)
 			if err != nil {
@@ -137,7 +143,7 @@ func (c chainUpdateTx) WalletRevertIndex(index types.ChainIndex, removed, unspen
 			} else if n, err := res.RowsAffected(); err != nil {
 				return fmt.Errorf("failed to get rows affected: %w", err)
 			} else if n != 1 {
-				return fmt.Errorf("failed to delete removed output: no rows affected")
+				return fmt.Errorf("failed to delete removed output: %w", ssql.ErrOutputNotFound)
 			}
 		}
 	}