diff --git a/app.json b/app.json
index a369176..e8b2faf 100644
--- a/app.json
+++ b/app.json
@@ -10,7 +10,7 @@
     "ios": {
       "supportsTablet": true,
       "bundleIdentifier": "com.beenvoice.app",
-      "buildNumber": "18",
+      "buildNumber": "20",
       "icon": "./assets/beenvoice.icon",
       "infoPlist": {
         "ITSAppUsesNonExemptEncryption": false,
diff --git a/app/(auth)/index.tsx b/app/(auth)/index.tsx
index 395cf3e..fe31b03 100644
--- a/app/(auth)/index.tsx
+++ b/app/(auth)/index.tsx
@@ -1,5 +1,12 @@
 import { Redirect } from "expo-router";
+import { useAccounts } from "@/contexts/AccountsContext";
 
 export default function AuthIndex() {
+  const { accounts, activeAccountId } = useAccounts();
+
+  if (!activeAccountId && accounts.length > 0) {
+    return <Redirect href="/(auth)/select-account" />;
+  }
+
   return <Redirect href="/(auth)/sign-in" />;
 }
diff --git a/app/(auth)/select-account.tsx b/app/(auth)/select-account.tsx
new file mode 100644
index 0000000..9cf8e51
--- /dev/null
+++ b/app/(auth)/select-account.tsx
@@ -0,0 +1,159 @@
+import { Ionicons } from "@expo/vector-icons";
+import { Redirect, router } from "expo-router";
+import { useState } from "react";
+import { ActivityIndicator, Pressable, StyleSheet, Text, View } from "react-native";
+
+import { AuthCard } from "@/components/auth/AuthCard";
+import { AuthCardHeader } from "@/components/auth/AuthCardHeader";
+import { AuthScreenLayout } from "@/components/auth/AuthScreenLayout";
+import { Button } from "@/components/ui/Button";
+import { fonts, radii, spacing } from "@/constants/theme";
+import { useAccounts } from "@/contexts/AccountsContext";
+import { useAppTheme } from "@/contexts/ThemeContext";
+import { startAdditionalAccountSignIn } from "@/lib/add-account";
+import { formatServerHost } from "@/lib/server-mode";
+
+function initials(name: string, email: string) {
+  const source = name.trim() || email.trim();
+  const parts = source.split(/\s+/).filter(Boolean);
+  if (parts.length >= 2) {
+    return `${parts[0]![0] ?? ""}${parts[1]![0] ?? ""}`.toUpperCase();
+  }
+  return (source[0] ?? "?").toUpperCase();
+}
+
+export default function SelectAccountScreen() {
+  const { colors } = useAppTheme();
+  const { accounts, activeAccountId, switchAccount, clearActiveAccount } = useAccounts();
+  const [selectingId, setSelectingId] = useState<string | null>(null);
+  const [adding, setAdding] = useState(false);
+
+  async function handleSelect(accountId: string) {
+    if (selectingId) return;
+    setSelectingId(accountId);
+    try {
+      await switchAccount(accountId);
+      router.replace("/(auth)/sign-in");
+    } finally {
+      setSelectingId(null);
+    }
+  }
+
+  async function handleAddAccount() {
+    if (adding) return;
+    setAdding(true);
+    try {
+      await startAdditionalAccountSignIn(clearActiveAccount);
+    } finally {
+      setAdding(false);
+    }
+  }
+
+  if (activeAccountId || accounts.length === 0) {
+    return <Redirect href="/(auth)/sign-in" />;
+  }
+
+  return (
+    <AuthScreenLayout>
+      <AuthCard>
+        <AuthCardHeader
+          title="Choose account"
+          description="Select the workspace account to use on this device"
+        />
+
+        <View style={styles.list}>
+          {accounts.map((account) => {
+            const isSelecting = selectingId === account.id;
+
+            return (
+              <Pressable
+                accessibilityRole="button"
+                disabled={Boolean(selectingId)}
+                key={account.id}
+                onPress={() => void handleSelect(account.id)}
+                style={({ pressed }) => [
+                  styles.accountRow,
+                  { backgroundColor: colors.muted, borderColor: colors.border },
+                  pressed && styles.pressed,
+                ]}
+              >
+                <View style={[styles.avatar, { backgroundColor: colors.primary }]}>
+                  <Text style={[styles.avatarText, { color: colors.primaryForeground }]}>
+                    {initials(account.name, account.email)}
+                  </Text>
+                </View>
+                <View style={styles.accountMeta}>
+                  <Text style={[styles.accountName, { color: colors.foreground }]}>
+                    {account.name || account.email}
+                  </Text>
+                  <Text style={[styles.accountSub, { color: colors.mutedForeground }]}>
+                    {account.email}
+                  </Text>
+                  <Text style={[styles.accountSub, { color: colors.mutedForeground }]}>
+                    {formatServerHost(account.instanceUrl)}
+                  </Text>
+                </View>
+                {isSelecting ? (
+                  <ActivityIndicator color={colors.primary} size="small" />
+                ) : (
+                  <Ionicons name="chevron-forward" size={18} color={colors.mutedForeground} />
+                )}
+              </Pressable>
+            );
+          })}
+        </View>
+
+        <Button
+          disabled={Boolean(selectingId)}
+          loading={adding}
+          onPress={() => void handleAddAccount()}
+          title="Sign in to another account"
+          variant="secondary"
+        />
+      </AuthCard>
+    </AuthScreenLayout>
+  );
+}
+
+const styles = StyleSheet.create({
+  list: {
+    gap: spacing.sm,
+  },
+  accountRow: {
+    minHeight: 72,
+    borderRadius: radii.lg,
+    borderWidth: 1,
+    flexDirection: "row",
+    alignItems: "center",
+    gap: spacing.md,
+    padding: spacing.md,
+  },
+  avatar: {
+    width: 36,
+    height: 36,
+    borderRadius: 18,
+    alignItems: "center",
+    justifyContent: "center",
+  },
+  avatarText: {
+    fontFamily: fonts.bodySemiBold,
+    fontSize: 13,
+  },
+  accountMeta: {
+    flex: 1,
+    gap: 2,
+  },
+  accountName: {
+    fontFamily: fonts.bodySemiBold,
+    fontSize: 15,
+    lineHeight: 20,
+  },
+  accountSub: {
+    fontFamily: fonts.body,
+    fontSize: 12,
+    lineHeight: 16,
+  },
+  pressed: {
+    opacity: 0.9,
+  },
+});
diff --git a/app/(auth)/sign-in.tsx b/app/(auth)/sign-in.tsx
index cbfd412..f2f3c1d 100644
--- a/app/(auth)/sign-in.tsx
+++ b/app/(auth)/sign-in.tsx
@@ -18,13 +18,14 @@ import { useAuthClient } from "@/contexts/AuthContext";
 import { useAppTheme } from "@/contexts/ThemeContext";
 import { fetchAuthCapabilities } from "@/lib/auth-capabilities";
 import { signInWithAuthentik } from "@/lib/auth-oauth";
+import { prepareAuthScreenSession } from "@/lib/auth-session";
 import { completeSignInAfterAuth } from "@/lib/complete-sign-in";
 import { formatAuthErrorMessage } from "@/lib/trpc-errors";
 import { isRequiredString, isValidEmail, useFieldVisibility } from "@/lib/form-validation";
 
 export default function SignInScreen() {
   const authClient = useAuthClient();
-  const { apiUrl, activeAccountId, registerAccount } = useAccounts();
+  const { apiUrl, activeAccountId, clearActiveAccount, registerAccount } = useAccounts();
   const { colors } = useAppTheme();
   const [email, setEmail] = useState("");
   const [password, setPassword] = useState("");
@@ -35,6 +36,10 @@ export default function SignInScreen() {
   const [signupsDisabled, setSignupsDisabled] = useState(false);
   const { touch, visible, markSubmitted } = useFieldVisibility();
 
+  useEffect(() => {
+    void prepareAuthScreenSession(authClient, activeAccountId, clearActiveAccount);
+  }, [authClient, activeAccountId, clearActiveAccount]);
+
   useEffect(() => {
     let cancelled = false;
 
diff --git a/app/_layout.tsx b/app/_layout.tsx
index b94e71e..369217f 100644
--- a/app/_layout.tsx
+++ b/app/_layout.tsx
@@ -103,12 +103,13 @@ export default function RootLayout() {
 
 function RootNavigator() {
   const { data: session, isPending } = useSession();
+  const { activeAccountId } = useAccounts();
 
   if (isPending) {
     return <LoadingScreen message="Checking session…" />;
   }
 
-  const isAuthenticated = Boolean(session?.user);
+  const isAuthenticated = Boolean(session?.user && activeAccountId);
 
   return (
     <Stack
diff --git a/contexts/AccountsContext.tsx b/contexts/AccountsContext.tsx
index 38039f8..ea36121 100644
--- a/contexts/AccountsContext.tsx
+++ b/contexts/AccountsContext.tsx
@@ -67,7 +67,7 @@ export function AccountsProvider({ children }: { children: ReactNode }) {
           setRuntimeApiUrl(active.instanceUrl);
         } else if (draftUrl) {
           setRuntimeApiUrl(draftUrl);
-        } else {
+        } else if (!process.env.EXPO_PUBLIC_API_URL?.trim()) {
           setRuntimeApiUrl(DEFAULT_API_URL);
         }
 
@@ -166,13 +166,8 @@ export function AccountsProvider({ children }: { children: ReactNode }) {
       await saveAccounts(nextAccounts);
 
       if (wasActive) {
-        const fallback = nextAccounts[0] ?? null;
-        await saveActiveAccountId(fallback?.id ?? null);
-        setActiveAccountId(fallback?.id ?? null);
-        if (fallback) {
-          setRuntimeApiUrl(fallback.instanceUrl);
-          setApiUrl(fallback.instanceUrl);
-        }
+        await saveActiveAccountId(null);
+        setActiveAccountId(null);
       }
 
       return { wasActive, remainingCount: nextAccounts.length };
diff --git a/lib/accounts.ts b/lib/accounts.ts
index d268e80..80e4628 100644
--- a/lib/accounts.ts
+++ b/lib/accounts.ts
@@ -13,6 +13,23 @@ export type SavedAccount = {
   lastUsedAt: number;
 };
 
+function isSavedAccount(value: unknown): value is SavedAccount {
+  if (!value || typeof value !== "object") return false;
+
+  const account = value as Partial<SavedAccount>;
+  return (
+    typeof account.id === "string" &&
+    account.id.length > 0 &&
+    typeof account.instanceUrl === "string" &&
+    account.instanceUrl.length > 0 &&
+    typeof account.userId === "string" &&
+    account.userId.length > 0 &&
+    typeof account.email === "string" &&
+    typeof account.name === "string" &&
+    typeof account.lastUsedAt === "number"
+  );
+}
+
 export function buildAccountId(instanceUrl: string, userId: string) {
   const host = instanceUrl.replace(/^https?:\/\//, "").replace(/\/$/, "");
   return `${host}::${userId}`;
@@ -26,8 +43,8 @@ export async function loadAccounts(): Promise<SavedAccount[]> {
   const raw = await AsyncStorage.getItem(ACCOUNTS_KEY);
   if (!raw) return [];
   try {
-    const parsed = JSON.parse(raw) as SavedAccount[];
-    return Array.isArray(parsed) ? parsed : [];
+    const parsed = JSON.parse(raw) as unknown;
+    return Array.isArray(parsed) ? parsed.filter(isSavedAccount) : [];
   } catch {
     return [];
   }
diff --git a/lib/auth-cookie.ts b/lib/auth-cookie.ts
index ffb603e..06ebc6d 100644
--- a/lib/auth-cookie.ts
+++ b/lib/auth-cookie.ts
@@ -2,6 +2,7 @@ import { getCookie as serializeStoredCookies } from "@better-auth/expo/client";
 import * as SecureStore from "expo-secure-store";
 import type { createAuthClient } from "better-auth/react";
 
+import { GUEST_AUTH_STORAGE_PREFIX } from "@/lib/auth-storage";
 import { normalizeSecureStoreKey } from "@/lib/secure-store-keys";
 
 type AuthClient = ReturnType<typeof createAuthClient>;
@@ -9,6 +10,7 @@ type AuthClient = ReturnType<typeof createAuthClient>;
 const CHUNK_MARKER = "\u0001ba-chunks:";
 const SESSION_TOKEN_COOKIE_PART =
   /(?:^|;\s*)(?:__Secure-)?[^=]*session_token=([^;]+)/;
+const AUTH_COOKIE_DEBUG = process.env.EXPO_PUBLIC_AUTH_COOKIE_DEBUG === "1";
 
 function readSecureStoreValueSync(key: string): string | null {
   const value = SecureStore.getItem(key);
@@ -27,16 +29,7 @@ function readSecureStoreValueSync(key: string): string | null {
   return assembled;
 }
 
-/** Read session cookie string for tRPC requests (Expo client plugin + SecureStore fallback). */
-export function getAuthCookie(
-  authClient: AuthClient,
-  storagePrefix: string,
-): string | null {
-  const fromClient = (
-    authClient as AuthClient & { getCookie?: () => string }
-  ).getCookie?.();
-  if (fromClient?.trim()) return fromClient.trim();
-
+function readStoredCookie(storagePrefix: string): string | null {
   const raw = readSecureStoreValueSync(
     normalizeSecureStoreKey(`${storagePrefix}_cookie`),
   );
@@ -46,14 +39,85 @@ export function getAuthCookie(
   return cookie.trim() || null;
 }
 
+function cookieNames(cookie: string): string[] {
+  return cookie
+    .split(";")
+    .map((part) => part.trim().split("=", 1)[0])
+    .filter(Boolean);
+}
+
+/** Read session cookie string for tRPC requests (Expo client plugin + SecureStore fallback). */
+export function getAuthCookie(
+  authClient: AuthClient,
+  storagePrefix: string,
+): string | null {
+  const fromClient = (
+    authClient as AuthClient & { getCookie?: () => string }
+  ).getCookie?.();
+  if (fromClient?.trim()) {
+    const cookie = fromClient.trim();
+    if (AUTH_COOKIE_DEBUG) {
+      console.info("[auth-cookie] using client cookie", {
+        storagePrefix,
+        length: cookie.length,
+        names: cookieNames(cookie),
+      });
+    }
+    return cookie;
+  }
+
+  const fromPrefix = readStoredCookie(storagePrefix);
+  if (fromPrefix) {
+    if (AUTH_COOKIE_DEBUG) {
+      console.info("[auth-cookie] using stored cookie", {
+        storagePrefix,
+        length: fromPrefix.length,
+        names: cookieNames(fromPrefix),
+      });
+    }
+    return fromPrefix;
+  }
+
+  const fromGuest =
+    storagePrefix === GUEST_AUTH_STORAGE_PREFIX
+      ? null
+      : readStoredCookie(GUEST_AUTH_STORAGE_PREFIX);
+  if (AUTH_COOKIE_DEBUG) {
+    console.info("[auth-cookie] resolved tRPC cookie", {
+      storagePrefix,
+      fallbackPrefix:
+        fromGuest && storagePrefix !== GUEST_AUTH_STORAGE_PREFIX
+          ? GUEST_AUTH_STORAGE_PREFIX
+          : null,
+      hasCookie: Boolean(fromGuest),
+      length: fromGuest?.length ?? 0,
+      names: fromGuest ? cookieNames(fromGuest) : [],
+    });
+  }
+  return fromGuest;
+}
+
 export function getAuthCookieHeaders(
   authClient: AuthClient,
   storagePrefix: string,
 ): Record<string, string> {
   const cookie = getAuthCookie(authClient, storagePrefix);
-  if (!cookie) return {};
+  if (!cookie) {
+    if (AUTH_COOKIE_DEBUG) {
+      console.info("[auth-cookie] no tRPC auth cookie", { storagePrefix });
+    }
+    return {};
+  }
 
   const sessionToken = cookie.match(SESSION_TOKEN_COOKIE_PART)?.[1];
+  if (AUTH_COOKIE_DEBUG) {
+    console.info("[auth-cookie] sending tRPC auth headers", {
+      storagePrefix,
+      cookieLength: cookie.length,
+      cookieNames: cookieNames(cookie),
+      hasSessionTokenHeader: Boolean(sessionToken),
+    });
+  }
   return {
     cookie,
     Cookie: cookie,
diff --git a/lib/auth-storage.ts b/lib/auth-storage.ts
index 2c08552..c5ca839 100644
--- a/lib/auth-storage.ts
+++ b/lib/auth-storage.ts
@@ -66,8 +66,13 @@ export async function readStoredSessionUser(prefix: string): Promise<{
   }
 }
 
-export async function migrateAuthStorage(fromPrefix: string, toPrefix: string): Promise<void> {
+export async function migrateAuthStorage(
+  fromPrefix: string,
+  toPrefix: string,
+  options: { clearSource?: boolean } = {},
+): Promise<void> {
   if (fromPrefix === toPrefix) return;
+  const clearSource = options.clearSource ?? true;
 
   await Promise.all(
     AUTH_STORAGE_SUFFIXES.map((suffix) =>
@@ -75,7 +80,9 @@ export async function migrateAuthStorage(fromPrefix: string, toPrefix: string):
     ),
   );
 
-  await clearAuthStorage(fromPrefix);
+  if (clearSource) {
+    await clearAuthStorage(fromPrefix);
+  }
 }
 
 export async function clearAuthStorage(prefix: string): Promise<void> {
@@ -124,7 +131,11 @@ export async function finalizeAuthenticatedAccount(input: {
     ? authStoragePrefix(input.activeAccountId)
     : GUEST_AUTH_STORAGE_PREFIX;
 
-  await migrateAuthStorage(sourcePrefix, targetPrefix);
+  if (sourcePrefix !== targetPrefix) {
+    await clearAuthStorage(targetPrefix);
+  }
+
+  await migrateAuthStorage(sourcePrefix, targetPrefix, { clearSource: false });
 
   await input.registerAccount({
     instanceUrl: input.apiUrl,