diff --git a/cmd/walletd/node.go b/cmd/walletd/node.go
index d40c8a4..008c835 100644
--- a/cmd/walletd/node.go
+++ b/cmd/walletd/node.go
@@ -167,6 +167,7 @@ func newNode(addr, dir string, chainNetwork string, useUPNP bool) (*node, error)
 	case "anagami":
 		network, genesisBlock = TestnetAnagami()
 		bootstrapPeers = anagamiBootstrap
+		testnetFixDBTree(dir)
 	default:
 		return nil, errors.New("invalid network: must be one of 'mainnet', 'zen', or 'anagami'")
 	}
diff --git a/cmd/walletd/testnet.go b/cmd/walletd/testnet.go
index 8d477cd..82a6892 100644
--- a/cmd/walletd/testnet.go
+++ b/cmd/walletd/testnet.go
@@ -6,9 +6,12 @@ import (
 	"log"
 	"math/big"
 	"os"
+	"path/filepath"
 	"reflect"
 	"time"
 
+	bolt "go.etcd.io/bbolt"
+	"go.sia.tech/core/chain"
 	"go.sia.tech/core/consensus"
 	"go.sia.tech/core/types"
 	"go.sia.tech/walletd/api"
@@ -380,3 +383,58 @@ func printTestnetTxpool(c *api.Client, seed wallet.Seed) {
 		}
 	}
 }
+
+func testnetFixDBTree(dir string) {
+	if _, err := os.Stat(filepath.Join(dir, "consensus.db")); err != nil {
+		log.Fatal(err)
+	}
+	bdb, err := bolt.Open(filepath.Join(dir, "consensus.db"), 0600, nil)
+	if err != nil {
+		log.Fatal(err)
+	}
+	db := &boltDB{db: bdb}
+	defer db.Close()
+	if db.Bucket([]byte("tree-fix")) != nil {
+		return
+	}
+
+	fmt.Print("Fixing consensus.db Merkle tree...")
+
+	network, genesisBlock := TestnetAnagami()
+	dbstore, tipState, err := chain.NewDBStore(db, network, genesisBlock)
+	if err != nil {
+		log.Fatal(err)
+	}
+	cm := chain.NewManager(dbstore, tipState)
+
+	bdb2, err := bolt.Open(filepath.Join(dir, "consensus.db-fixed"), 0600, nil)
+	if err != nil {
+		log.Fatal(err)
+	}
+	db2 := &boltDB{db: bdb2}
+	defer db2.Close()
+	dbstore2, tipState2, err := chain.NewDBStore(db2, network, genesisBlock)
+	if err != nil {
+		log.Fatal(err)
+	}
+	cm2 := chain.NewManager(dbstore2, tipState2)
+
+	for cm2.Tip() != cm.Tip() {
+		index, _ := cm.BestIndex(cm2.Tip().Height + 1)
+		b, _ := cm.Block(index.ID)
+		if err := cm2.AddBlocks([]types.Block{b}); err != nil {
+			log.Fatal(err)
+		}
+	}
+
+	if _, err := db2.CreateBucket([]byte("tree-fix")); err != nil {
+		log.Fatal(err)
+	} else if err := db.Close(); err != nil {
+		log.Fatal(err)
+	} else if err := db2.Close(); err != nil {
+		log.Fatal(err)
+	} else if err := os.Rename(filepath.Join(dir, "consensus.db-fixed"), filepath.Join(dir, "consensus.db")); err != nil {
+		log.Fatal(err)
+	}
+	fmt.Println("done.")
+}
diff --git a/internal/walletutil/manager.go b/internal/walletutil/manager.go
index 77b8d1f..185006b 100644
--- a/internal/walletutil/manager.go
+++ b/internal/walletutil/manager.go
@@ -244,6 +244,9 @@ func (wm *JSONWalletManager) AddWallet(name string, info json.RawMessage) error
 		// update existing wallet
 		mw.info = info
 		return wm.save()
+	} else if _, err := os.Stat(filepath.Join(wm.dir, "wallets", name+".json")); err == nil {
+		// shouldn't happen in normal conditions
+		return errors.New("a wallet with that name already exists, but is absent from wallets.json")
 	}
 	store, _, err := NewJSONStore(filepath.Join(wm.dir, "wallets", name+".json"))
 	if err != nil {