diff --git a/lib/sign-out-cleanup.ts b/lib/sign-out-cleanup.ts
index f7ca42832..0effb91ac 100644
--- a/lib/sign-out-cleanup.ts
+++ b/lib/sign-out-cleanup.ts
@@ -38,9 +38,10 @@ const SIGNED_OUT_STORAGE_KEYS = [
   'bulwark-offline-accounts',
   // Which accounts' data waits for a new sign-in, and until when.
   'bulwark-offline-evicted',
+  'bulwark-store-opened',
 ];
 
-const LOCAL_STORE_KEYS = new Set(['bulwark-offline-accounts', 'bulwark-offline-evicted']);
+const LOCAL_STORE_KEYS = new Set(['bulwark-offline-accounts', 'bulwark-offline-evicted', 'bulwark-store-opened']);
 
 const SIGNED_OUT_SIGNAL = 'bulwark:signed-out';
 
diff --git a/lib/store/__tests__/page-side.test.ts b/lib/store/__tests__/page-side.test.ts
index ede57905f..fbd336b69 100644
--- a/lib/store/__tests__/page-side.test.ts
+++ b/lib/store/__tests__/page-side.test.ts
@@ -1,9 +1,10 @@
 import 'fake-indexeddb/auto';
 import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
-import { configureStore, getStore, setStoreBackend } from '../client/api';
-import { getAccountRecord } from '../client/keys';
+import { configureStore, getStore, setStoreBackend, STORE_OPENED_KEY } from '../client/api';
+import { forgetAccountKey, getAccountRecord } from '../client/keys';
 import { purgeStoreFiles } from '../client/purge';
-import { StoreClient } from '../client/store-client';
+import { StoreClient, StoreOwnerGoneError } from '../client/store-client';
+import { storeFilesToPrune } from '../worker/host';
 import { FAKE_SESSION } from './helpers/fake-jmap';
 
 /** Everything on one page: a BroadcastChannel that also reaches other objects here, as in a browser. */
@@ -25,6 +26,7 @@ class FakeChannel {
 
 class FakeWorker {
   static all: FakeWorker[] = [];
+  static openResult: unknown;
   onmessage: ((event: MessageEvent) => void) | null = null;
   posted: Array<Record<string, unknown>> = [];
   terminated = false;
@@ -33,7 +35,7 @@ class FakeWorker {
   }
   postMessage(message: Record<string, unknown>): void {
     this.posted.push(message);
-    if (message.kind === 'open') queueMicrotask(() => this.onmessage?.({ data: { kind: 'result', id: message.id } } as MessageEvent));
+    if (message.kind === 'open' || message.kind === 'prune-files') queueMicrotask(() => this.onmessage?.({ data: { kind: 'result', id: message.id, result: message.kind === 'open' ? FakeWorker.openResult : undefined } } as MessageEvent));
   }
   terminate(): void {
     this.terminated = true;
@@ -107,6 +109,47 @@ describe('a tab that starts after the owner', () => {
   });
 });
 
+describe('an owner that stopped answering', () => {
+  afterEach(() => vi.useRealTimers());
+
+  async function clientWithOwner(answers: () => boolean) {
+    vi.useFakeTimers();
+    const owner = new FakeChannel('bulwark-store-rpc');
+    owner.onmessage = (event) => {
+      const data = event.data as { kind: string };
+      if (data.kind === 'who-owns' && answers()) owner.postMessage({ kind: 'owner-changed', owner: 'elsewhere' });
+    };
+    const client = new StoreClient({ basePath: '' });
+    client.start();
+    await vi.advanceTimersByTimeAsync(0);
+    return client;
+  }
+
+  it('stops its calls waiting, long before their own time limit', async () => {
+    let answering = true;
+    const client = await clientWithOwner(() => answering);
+    const call = client.sync('a@x');
+    const failed = vi.fn();
+    void call.catch(failed);
+    await vi.advanceTimersByTimeAsync(0);
+    answering = false;
+    await vi.advanceTimersByTimeAsync(39_000);
+    expect(failed).not.toHaveBeenCalled();
+    await vi.advanceTimersByTimeAsync(11_000);
+    expect(failed.mock.calls[0][0]).toBeInstanceOf(StoreOwnerGoneError);
+    client.halt();
+  });
+
+  it('leaves calls alone while the owner answers', async () => {
+    const client = await clientWithOwner(() => true);
+    const failed = vi.fn();
+    void client.sync('a@x').catch(failed);
+    await vi.advanceTimersByTimeAsync(10 * 60_000);
+    expect(failed).not.toHaveBeenCalled();
+    client.halt();
+  });
+});
+
 describe('the owner tab calling its own worker', () => {
   it('waits for the worker on the channel, since a call posted before that is lost', async () => {
     const worker = new FakeChannel('bulwark-store-rpc');
@@ -165,7 +208,7 @@ describe('purgeStoreFiles', () => {
     const order: string[] = [];
     Object.defineProperty(window.navigator, 'locks', {
       configurable: true,
-      value: { request: async (name: string, run: () => Promise<void>) => { order.push(`lock ${name}`); await run(); order.push('unlock'); } },
+      value: { request: async (name: string, _options: unknown, run: () => Promise<void>) => { order.push(`lock ${name}`); await run(); order.push('unlock'); } },
     });
     storage(async (name, options) => {
       order.push(`remove ${name} ${JSON.stringify(options)}`);
@@ -176,6 +219,25 @@ describe('purgeStoreFiles', () => {
     expect((await indexedDB.databases()).map((d) => d.name)).not.toContain('bulwark-store');
   });
 
+  it('deletes what it can when another tab never lets go of the owner lock', async () => {
+    const remove = vi.fn(async () => {});
+    storage(remove);
+    let waited: AbortSignal | undefined;
+    Object.defineProperty(window.navigator, 'locks', {
+      configurable: true,
+      value: {
+        // The browser gives up when the signal says so.
+        request: async (_name: string, options: { signal: AbortSignal }) => {
+          waited = options.signal;
+          throw new DOMException('Took too long', 'TimeoutError');
+        },
+      },
+    });
+    await purgeStoreFiles();
+    expect(waited).toBeInstanceOf(AbortSignal);
+    expect(remove).toHaveBeenCalledTimes(1);
+  });
+
   it('waits out a worker that still holds the files, and shrugs at a pool that isn\'t there', async () => {
     const remove = vi.fn()
       .mockRejectedValueOnce(Object.assign(new Error('busy'), { name: 'NoModificationAllowedError' }))
@@ -189,6 +251,12 @@ describe('purgeStoreFiles', () => {
   });
 });
 
+describe('which files have no key', () => {
+  it('names store files with no key, and leaves anything else alone', () => {
+    expect(storeFilesToPrune(['/a01.db', '/a02.db', '/a02.db-journal', '/other', '/ab.DB'], ['/a02.db'])).toEqual(['/a01.db']);
+  });
+});
+
 describe('the page\'s store', () => {
   function allowEngine() {
     configureStore({
@@ -214,6 +282,84 @@ describe('the page\'s store', () => {
     expect(worker.terminated).toBe(true);
   });
 
+  describe('when the key or the file of a store is gone', () => {
+    const lost = vi.fn();
+    const open = async () => {
+      configureStore({
+        inputs: () => ({ session: FAKE_SESSION, auth: 'Basic x', invertedKeywordSort: true }),
+        refreshAuth: async () => null,
+        onEvent: () => {},
+        onStoreLost: lost,
+      });
+      const store = getStore();
+      await store.ensureOpen('lost@x');
+      const worker = FakeWorker.all[FakeWorker.all.length - 1];
+      worker.becomeOwner();
+      await vi.waitFor(() => expect(worker.posted.some((m) => m.kind === 'open')).toBe(true));
+      await vi.waitFor(() => expect(localStorage.getItem(STORE_OPENED_KEY)).toContain('lost@x'));
+      store.stop();
+      return worker;
+    };
+
+    beforeEach(() => {
+      lost.mockClear();
+      localStorage.clear();
+    });
+
+    afterEach(async () => {
+      await forgetAccountKey('lost@x');
+    });
+
+    it('stays quiet about a first open, and removes nothing a key still names', async () => {
+      const worker = await open();
+      expect(lost).not.toHaveBeenCalled();
+      const prune = worker.posted.find((m) => m.kind === 'prune-files') as unknown as { keep: string[] };
+      const record = await getAccountRecord('lost@x');
+      expect(prune.keep).toContain(record!.file);
+    });
+
+    it('deletes the orphan and tells the page when the key went', async () => {
+      await open();
+      const before = await getAccountRecord('lost@x');
+      await forgetAccountKey('lost@x');
+      const worker = await open();
+      const after = await getAccountRecord('lost@x');
+      expect(after!.file).not.toBe(before!.file);
+      const prune = worker.posted.find((m) => m.kind === 'prune-files') as unknown as { keep: string[] };
+      expect(prune.keep).toContain(after!.file);
+      expect(prune.keep).not.toContain(before!.file);
+      expect(lost).toHaveBeenCalledWith('lost@x');
+    });
+
+    it('stays quiet on a normal reopen', async () => {
+      await open();
+      const worker = await open();
+      expect(lost).not.toHaveBeenCalled();
+      expect(worker.posted.some((m) => m.kind === 'prune-files')).toBe(false);
+    });
+
+    it('tells the page when the file went and the key stayed', async () => {
+      await open();
+      FakeWorker.openResult = { created: true };
+      try {
+        await open();
+      } finally {
+        FakeWorker.openResult = undefined;
+      }
+      expect(lost).toHaveBeenCalledWith('lost@x');
+    });
+
+    it('doesn\'t remember an account that was removed', async () => {
+      await open();
+      vi.spyOn(StoreClient.prototype, 'removeAccount').mockResolvedValue(true as never);
+      await getStore().remove('lost@x');
+      getStore().stop();
+      vi.restoreAllMocks();
+      await open();
+      expect(lost).not.toHaveBeenCalled();
+    });
+  });
+
   it('runs the client\'s refresh when the worker needs auth, and hands the result over', async () => {
     allowEngine();
     const store = getStore();
diff --git a/lib/store/client/api.ts b/lib/store/client/api.ts
index 09cb18af2..83cb83655 100644
--- a/lib/store/client/api.ts
+++ b/lib/store/client/api.ts
@@ -7,7 +7,7 @@
 
 import { DEFAULT_SCOPE, type StoreEvent, type StoreScope } from '../area';
 import type { JmapResponse, MethodCall, StoreSession } from '../engine/transport';
-import { forgetAccountKey, getAccountRecord, openAccountKey, type WrapLayer } from './keys';
+import { forgetAccountKey, getAccountRecord, knownStoreFiles, openAccountKey, type WrapLayer } from './keys';
 import { StoreClient } from './store-client';
 
 export interface StoreAccountInputs {
@@ -25,6 +25,8 @@ export interface StorePageHooks {
   onEvent(event: StoreEvent): void;
   /** Wrap layers on top of the WebCrypto one (desktop keychain, app lock). */
   keyLayers?(): readonly WrapLayer[];
+  /** An account this device kept mail for has an empty store now: its key or its file went. */
+  onStoreLost?(account: string): void;
 }
 
 /** What lib/offline uses. A seam, so its tests run the real engine on node:sqlite. */
@@ -49,6 +51,30 @@ export interface StoreBackend {
 const OPEN_RETRIES = 25;
 const OPEN_RETRY_MS = 200;
 
+/**
+ * localStorage: accounts that have had a store here. Holds nothing but the
+ * account's id, and it outlives what a browser may clear of the rest.
+ */
+export const STORE_OPENED_KEY = 'bulwark-store-opened';
+
+function readOpenedAccounts(): string[] {
+  try {
+    const parsed = JSON.parse(localStorage.getItem(STORE_OPENED_KEY) ?? '[]') as unknown;
+    return Array.isArray(parsed) ? parsed as string[] : [];
+  } catch {
+    return [];
+  }
+}
+
+function rememberOpened(account: string, opened: boolean): void {
+  try {
+    const others = readOpenedAccounts().filter((id) => id !== account);
+    localStorage.setItem(STORE_OPENED_KEY, JSON.stringify(opened ? [...others, account] : others));
+  } catch {
+    // Without it a lost store goes unnoticed, and the store still works.
+  }
+}
+
 class PageStore implements StoreBackend {
   private client: StoreClient | null = null;
   private readonly wanted = new Map<string, StoreSession | null>();
@@ -104,10 +130,12 @@ class PageStore implements StoreBackend {
     if (running) return running;
     const run = (async () => {
       const client = this.started();
-      const { keyHex, record } = await openAccountKey(account, this.hooks()?.keyLayers?.() ?? []);
+      const { keyHex, record, fresh } = await openAccountKey(account, this.hooks()?.keyLayers?.() ?? []);
+      // The old file, if the key alone went, can never be read again.
+      if (fresh) await client.pruneFiles(await knownStoreFiles()).catch(() => {});
       const inputs = this.hooks()?.inputs(account) ?? { session: null, auth: null, invertedKeywordSort: null };
       if (inputs.scope) this.sentScope.set(account, JSON.stringify(inputs.scope));
-      await client.openAccount({
+      const opened = await client.openAccount({
         account,
         file: record.file,
         keyHex,
@@ -116,6 +144,10 @@ class PageStore implements StoreBackend {
         invertedKeywordSort: inputs.invertedKeywordSort,
         auth: inputs.auth,
       });
+      if (fresh || opened?.created) {
+        if (readOpenedAccounts().includes(account)) this.hooks()?.onStoreLost?.(account);
+      }
+      rememberOpened(account, true);
     })();
     this.opening.set(account, run);
     run.catch(() => this.opening.delete(account));
@@ -183,6 +215,7 @@ class PageStore implements StoreBackend {
   async remove(account: string): Promise<void> {
     const record = await getAccountRecord(account);
     await forgetAccountKey(account);
+    rememberOpened(account, false);
     this.wanted.delete(account);
     this.opening.delete(account);
     if (record && !this.broken) await this.started().removeAccount(account, record.file);
diff --git a/lib/store/client/keys.ts b/lib/store/client/keys.ts
index ecd4fe4c2..9723c6710 100644
--- a/lib/store/client/keys.ts
+++ b/lib/store/client/keys.ts
@@ -83,6 +83,14 @@ export function newStoreFileName(): string {
   return `/a${toHex(crypto.getRandomValues(new Uint8Array(8)))}.db`;
 }
 
+/** The file of every account with a key. Any other file in the pool can't be read by anyone. */
+export async function knownStoreFiles(): Promise<string[]> {
+  return withDb(async (db) => {
+    const records = await promisify(db.transaction(ACCOUNTS, 'readonly').objectStore(ACCOUNTS).getAll()) as AccountRecord[];
+    return records.map((record) => record.file);
+  });
+}
+
 export async function getAccountRecord(account: string): Promise<AccountRecord | null> {
   return withDb(async (db) => {
     const found = await promisify(db.transaction(ACCOUNTS, 'readonly').objectStore(ACCOUNTS).get(account)) as AccountRecord | undefined;
@@ -95,7 +103,7 @@ export async function listAccountRecords(): Promise<AccountRecord[]> {
 }
 
 /** The account's key in hex, created on first use. Returns the record too, for the file name. */
-export async function openAccountKey(account: string, layers: readonly WrapLayer[] = []): Promise<{ keyHex: string; record: AccountRecord }> {
+export async function openAccountKey(account: string, layers: readonly WrapLayer[] = []): Promise<{ keyHex: string; record: AccountRecord; fresh: boolean }> {
   return withDb(async (db) => {
     const wrapping = await wrapKey(db);
     const found = await promisify(db.transaction(ACCOUNTS, 'readonly').objectStore(ACCOUNTS).get(account)) as AccountRecord | undefined;
@@ -109,7 +117,7 @@ export async function openAccountKey(account: string, layers: readonly WrapLayer
       const raw = new Uint8Array(await crypto.subtle.decrypt({ name: 'AES-GCM', iv: asBuffer(found.iv) }, wrapping, asBuffer(data)));
       const keyHex = toHex(raw);
       raw.fill(0);
-      return { keyHex, record: found };
+      return { keyHex, record: found, fresh: false };
     }
     const raw = crypto.getRandomValues(new Uint8Array(32));
     const iv = crypto.getRandomValues(new Uint8Array(12));
@@ -126,7 +134,7 @@ export async function openAccountKey(account: string, layers: readonly WrapLayer
     await promisify(db.transaction(ACCOUNTS, 'readwrite').objectStore(ACCOUNTS).put(record));
     const keyHex = toHex(raw);
     raw.fill(0);
-    return { keyHex, record };
+    return { keyHex, record, fresh: true };
   });
 }
 
diff --git a/lib/store/client/purge.ts b/lib/store/client/purge.ts
index c2356dd34..10fb04dfb 100644
--- a/lib/store/client/purge.ts
+++ b/lib/store/client/purge.ts
@@ -10,6 +10,8 @@ import { deleteKeyDatabase } from './keys';
 /** A worker just stopped may hold the files for a moment longer. */
 const REMOVE_TRIES = 10;
 const REMOVE_WAIT_MS = 200;
+/** A sign-out doesn't wait for a tab that never lets go of the owner lock. */
+const POOL_LOCK_WAIT_MS = 5_000;
 
 async function removePool(): Promise<void> {
   const root = await navigator.storage.getDirectory();
@@ -28,8 +30,18 @@ async function removePool(): Promise<void> {
 /** Deletes the pool folder, holding the owner lock so no worker can take the files meanwhile. */
 export async function deleteStorePool(): Promise<void> {
   if (typeof navigator === 'undefined' || typeof navigator.storage?.getDirectory !== 'function') return;
-  if (navigator.locks) await navigator.locks.request(OWNER_LOCK, removePool);
-  else await removePool();
+  if (!navigator.locks) {
+    await removePool();
+    return;
+  }
+  try {
+    await navigator.locks.request(OWNER_LOCK, { signal: AbortSignal.timeout(POOL_LOCK_WAIT_MS) }, removePool);
+  } catch (error) {
+    if ((error as Error)?.name !== 'TimeoutError' && (error as Error)?.name !== 'AbortError') throw error;
+    // A tab that won't let go, stuck or asleep: the key is gone, so what can be
+    // deleted goes now, and what it still holds can't be read anyway.
+    await removePool();
+  }
 }
 
 /**
diff --git a/lib/store/client/store-client.ts b/lib/store/client/store-client.ts
index 13b4af661..66e7c3b92 100644
--- a/lib/store/client/store-client.ts
+++ b/lib/store/client/store-client.ts
@@ -21,6 +21,9 @@ import {
 
 const CALL_TIMEOUT_MS = 60_000;
 const OWNER_WAIT_MS = 15_000;
+/** Calls waiting on the owner ask it this often whether it's still there. */
+const OWNER_PING_MS = 10_000;
+const OWNER_PING_MISSES = 3;
 /** A first sync of a large account runs a long time, and its promise is what ends "syncing". */
 const SYNC_TIMEOUT_MS = 30 * 60_000;
 
@@ -58,6 +61,8 @@ export class StoreClient {
   private isOwner = false;
   private readonly pending = new Map<string, Pending>();
   private readonly ownerWaiters: Array<() => void> = [];
+  private ownerWatch: ReturnType<typeof setInterval> | null = null;
+  private ownerAnswered: (() => void) | null = null;
   private lifecycleBound = false;
 
   constructor(private readonly options: StoreClientOptions = {}) {}
@@ -150,6 +155,7 @@ export class StoreClient {
         break;
       case 'owner-changed':
         this.owner = message.owner;
+        if (message.owner) this.ownerAnswered?.();
         if (message.owner) this.flushOwnerWaiters();
         break;
       case 'shutdown':
@@ -175,6 +181,41 @@ export class StoreClient {
     }
   }
 
+  /**
+   * A tab that's frozen or stuck keeps the lock, and nothing else would tell.
+   * While calls wait, the owner is asked to answer; when it doesn't for a while,
+   * they stop waiting instead of running into their long time limits.
+   */
+  private watchOwner(): void {
+    if (this.ownerWatch) return;
+    let unanswered = 0;
+    this.ownerAnswered = () => { unanswered = 0; };
+    this.ownerWatch = setInterval(() => {
+      if (this.pending.size === 0) {
+        this.stopWatchingOwner();
+        return;
+      }
+      if (unanswered >= OWNER_PING_MISSES) {
+        this.owner = null;
+        this.stopWatchingOwner();
+        for (const [id, pending] of this.pending) {
+          this.pending.delete(id);
+          clearTimeout(pending.timer);
+          pending.reject(new StoreOwnerGoneError());
+        }
+        return;
+      }
+      unanswered += 1;
+      this.channel?.postMessage({ kind: 'who-owns' } satisfies ChannelMessage);
+    }, OWNER_PING_MS);
+  }
+
+  private stopWatchingOwner(): void {
+    if (this.ownerWatch) clearInterval(this.ownerWatch);
+    this.ownerWatch = null;
+    this.ownerAnswered = null;
+  }
+
   private flushOwnerWaiters(): void {
     for (const waiter of this.ownerWaiters.splice(0)) waiter();
   }
@@ -202,6 +243,7 @@ export class StoreClient {
 
   private async rpc<K extends keyof StoreRpc>(method: K, params: Parameters<StoreRpc[K]>[0], timeoutMs = CALL_TIMEOUT_MS): Promise<ReturnType<StoreRpc[K]>> {
     await this.waitForOwner();
+    this.watchOwner();
     const id = crypto.randomUUID();
     const result = this.track<ReturnType<StoreRpc[K]>>(id, timeoutMs);
     this.channel?.postMessage({ kind: 'rpc', id, from: this.clientId, method, params } as ChannelMessage);
@@ -220,10 +262,16 @@ export class StoreClient {
     return this.isOwner;
   }
 
-  openAccount(params: OpenAccountParams): Promise<void> {
+  /** `created`: there was no database under this name. */
+  openAccount(params: OpenAccountParams): Promise<{ created?: boolean } | undefined> {
     return this.direct({ kind: 'open', id: crypto.randomUUID(), params });
   }
 
+  /** Deletes every store file but these. */
+  pruneFiles(keep: string[]): Promise<void> {
+    return this.direct({ kind: 'prune-files', id: crypto.randomUUID(), keep });
+  }
+
   closeAccount(account: string): Promise<void> {
     return this.direct({ kind: 'close-account', id: crypto.randomUUID(), account });
   }
@@ -266,6 +314,7 @@ export class StoreClient {
     this.channel = null;
     this.isOwner = false;
     this.owner = null;
+    this.stopWatchingOwner();
     for (const [id, pending] of this.pending) {
       this.pending.delete(id);
       clearTimeout(pending.timer);
diff --git a/lib/store/worker/host.ts b/lib/store/worker/host.ts
index 9b56b594b..3a2a7036f 100644
--- a/lib/store/worker/host.ts
+++ b/lib/store/worker/host.ts
@@ -9,6 +9,11 @@ import { FetchTransport, type StoreSession } from '../engine/transport';
 import type { StorageAdapter } from '../storage';
 import type { OpenAccountParams, StoreRpc, StoreStatus } from './protocol';
 
+/** Files in the pool that belong to no key. A name that isn't a store file's is left alone. */
+export function storeFilesToPrune(files: readonly string[], keep: readonly string[]): string[] {
+  return files.filter((file) => /^\/a[0-9a-f]+\.db$/.test(file) && !keep.includes(file));
+}
+
 export interface HostStorage {
   open(file: string, keyHex: string): Promise<StorageAdapter>;
   remove(file: string): boolean;
@@ -44,7 +49,7 @@ export class StoreHost {
 
   constructor(private readonly options: StoreHostOptions) {}
 
-  async openAccount(params: OpenAccountParams): Promise<void> {
+  async openAccount(params: OpenAccountParams): Promise<{ created: boolean }> {
     const existing = this.accounts.get(params.account);
     if (existing) {
       if (params.session) this.setSession(params.account, params.session);
@@ -52,9 +57,10 @@ export class StoreHost {
       existing.engine.setScope(params.scope);
       if (params.invertedKeywordSort !== null) existing.engine.setInvertedKeywordSort(params.invertedKeywordSort);
       void existing.engine.requestSync();
-      return;
+      return { created: false };
     }
     const db = await this.options.storage.open(params.file, params.keyHex);
+    const created = !db.get("SELECT 1 AS yes FROM sqlite_master WHERE name = 'schema_migration'");
     const session = params.session ?? AccountEngine.storedSession(db);
     if (!session) {
       db.close();
@@ -85,6 +91,7 @@ export class StoreHost {
     account.engine.setOnline(this.online);
     this.accounts.set(params.account, account);
     void account.engine.requestSync();
+    return { created };
   }
 
   setAuth(account: string, auth: string | null): void {
diff --git a/lib/store/worker/protocol.ts b/lib/store/worker/protocol.ts
index eefd34f96..5fefc7e0f 100644
--- a/lib/store/worker/protocol.ts
+++ b/lib/store/worker/protocol.ts
@@ -75,6 +75,7 @@ export type PageToWorker =
   | { kind: 'init'; clientId: string; moduleUrl: string }
   | { kind: 'open'; id: string; params: OpenAccountParams }
   | { kind: 'close-account'; id: string; account: string }
+  | { kind: 'prune-files'; id: string; keep: string[] }
   | { kind: 'set-auth'; account: string; auth: string | null }
   | { kind: 'set-inverted'; account: string; inverted: boolean }
   | { kind: 'set-session'; account: string; session: StoreSession }
diff --git a/lib/store/worker/worker.ts b/lib/store/worker/worker.ts
index 52e1c3688..a41ee1405 100644
--- a/lib/store/worker/worker.ts
+++ b/lib/store/worker/worker.ts
@@ -9,7 +9,7 @@
 import { WasmStorage } from '../adapters/wasm';
 import { STORE_AREAS } from '../areas';
 import { RPC_CHANNEL, OWNER_LOCK, type ChannelMessage, type PageToWorker, type WorkerToPage } from './protocol';
-import { StoreHost } from './host';
+import { StoreHost, storeFilesToPrune } from './host';
 
 const scope = self as unknown as {
   postMessage(message: WorkerToPage): void;
@@ -110,7 +110,14 @@ scope.addEventListener('message', async (event) => {
       break;
     case 'open':
       try {
-        await requireHost().openAccount(message.params);
+        reply(message.id, await requireHost().openAccount(message.params));
+      } catch (error) {
+        replyError(message.id, error);
+      }
+      break;
+    case 'prune-files':
+      try {
+        for (const file of storeFilesToPrune(storage?.files() ?? [], message.keep)) storage?.remove(file);
         reply(message.id);
       } catch (error) {
         replyError(message.id, error);