Fixing React Native Secure Storage Data That Silently Disappears After an iOS Reinstall

The Problem

A React Native app stores sensitive data — an auth token, encrypted offline records, a biometric-protected credential — using a secure storage library backed by iOS Keychain. The data persists correctly across normal app updates (installing a new version over an existing one). But when a user deletes the app entirely and reinstalls it later — a common reason being to free up device storage — the previously stored data is simply gone, with no error reported anywhere in the process; the app just behaves as if it were a fresh install with nothing ever saved.

Why It Happens

iOS Keychain items can be configured to survive an app deletion, but it isn't the default for every access attribute

Keychain items have an accessibility attribute controlling exactly this behavior. Some values (like kSecAttrAccessibleWhenUnlocked) are tied to the app's install lifecycle in ways that can result in the item being removed when the app is deleted, while others are specifically designed to persist across a delete-and-reinstall cycle. Many secure storage libraries pick a sensible-looking default that isn't necessarily the one that survives deletion, and unless a developer deliberately configures otherwise, the library's default silently determines this behavior.

This distinction is invisible during typical development, where reinstalls are rare compared to rebuilds

During active development, a developer overwhelmingly experiences the "install a new build over the existing one" path via Xcode or Metro — a genuine delete-then-reinstall cycle, the specific scenario that exposes this behavior, is something a developer rarely does deliberately unless specifically testing for it, which is exactly why this gets discovered from real user reports rather than caught in-house.

Different libraries and even different versions of the same library can default to different Keychain accessibility settings

A library migration, a major version upgrade, or simply using two different secure-storage packages across different parts of an app can introduce inconsistent accessibility settings across the data an app stores, meaning some values survive a reinstall while others — stored via a different code path or library — don't, producing a confusing, partial-data-loss symptom rather than a clean all-or-nothing failure.

The underlying device Keychain itself can also be affected by iCloud Keychain sync settings in ways that compound the confusion

If iCloud Keychain sync is involved, Keychain data's behavior across a reinstall can additionally depend on sync state and whether the item was configured to sync in the first place — adding another variable that can make the same symptom reproduce inconsistently across different test devices or user reports.

The Fix

1. Deliberately choose and set the Keychain accessibility level that matches the app's actual requirement

import * as Keychain from "react-native-keychain";

await Keychain.setGenericPassword("username", "token", {
  accessible: Keychain.ACCESSIBLE.WHEN_UNLOCKED_THIS_DEVICE_ONLY,
  // Explicitly choose based on whether data SHOULD survive a reinstall
});

Explicitly setting the accessibility option, rather than relying on whatever a library's default happens to be, is the direct lever for this behavior — the right choice depends on the actual requirement: if a credential is genuinely meant to require re-authentication after a full reinstall (arguably more secure), that's a deliberate choice rather than an accident; if it's meant to persist, the accessibility level needs to reflect that intentionally.

2. Treat a reinstall-triggered data loss as an expected possibility in app logic, not an edge case to ignore

async function getStoredToken() {
  const credentials = await Keychain.getGenericPassword();
  if (!credentials) {
    // Could be a genuinely fresh install, OR a reinstall where Keychain
    // data didn't survive — the app can't always distinguish these,
    // so route to a normal re-authentication flow either way
    return null;
  }
  return credentials.password;
}

Designing the app's auth or data-restoration flow to gracefully handle "nothing found" as a normal, expected case — rather than assuming stored data will always be present after a first app launch — means a reinstall-triggered gap degrades to a re-login prompt rather than a confusing crash or broken state.

3. Audit all secure storage call sites for consistent accessibility configuration

grep -rn "setGenericPassword|SecItemAdd|Keychain.set" src/
# Check each call site uses the same, deliberately chosen accessibility option

Searching the codebase for every place secure storage is actually written to and confirming they all use a consistent, deliberately chosen accessibility setting catches the specific case where a library update, a different package, or a different developer introduced an inconsistent default somewhere in the app.

4. Test the actual delete-and-reinstall scenario explicitly, not just rebuild-over-existing

# Fully delete the app from the device/simulator, not just reinstall over it
xcrun simctl uninstall booted com.company.appname
npx react-native run-ios
# Then check whether previously stored Keychain data is actually still present

Explicitly testing the delete-then-reinstall path as a distinct test case — not assuming a normal rebuild exercises the same scenario — is the only way to directly confirm the chosen accessibility setting actually produces the intended behavior, rather than discovering the gap from a user's bug report after release.

Why This Works

Each fix addresses a different point in how Keychain persistence across reinstalls is both configured and verified. Explicitly choosing the accessibility level makes the survive-or-not behavior a deliberate decision rather than an accidental library default; designing around a possible missing value treats the scenario as expected rather than exceptional; auditing for consistency catches drift introduced by library changes over time; and testing the actual delete-reinstall cycle directly confirms the configuration does what it's intended to, closing the gap between what the code says and what iOS actually does with it.

Conclusion

Secure storage data disappearing after a reinstall isn't the storage library failing — it's an iOS Keychain accessibility setting, often left at a library's default rather than deliberately chosen, determining whether data survives a delete-and-reinstall cycle differently than it survives a normal update. Explicitly set the Keychain accessibility level to match the actual requirement, design the app to handle a missing value gracefully regardless of its cause, audit all storage call sites for consistent configuration, and test the genuine delete-then-reinstall scenario directly rather than relying on a rebuild-over-existing test to stand in for it.