## TL;DR

Update the Tailscale Android app to version 1.86 or newer. Version 1.84 introduced a taildrop directory picker that registered a second node key; 1.86 defers the picker until you actually receive a file, which stops the duplicate key warning.

## The error

```text
Duplicate Node key
```

Shown in the Tailscale admin console for the Android device after updating the app.

## Fix it

1. Open the Google Play Store on the Android device and check the installed Tailscale version.
   Success check: the version is below 1.86, confirming you are affected.

2. Update Tailscale to 1.86 or newer.
   Success check: the Play Store shows the update installed with no errors.

3. Open the Tailscale admin console and find the Android device.
   Success check: only one node key entry remains; the duplicate warning is gone.

4. If a stale duplicate entry lingers, remove the old machine entry from the admin console.
   Success check: the device list shows a single entry for the phone.

## When this applies

- Tailscale on Android, app version 1.84 or 1.85, admin console shows 'Duplicate Node key' after an update.
- The duplicate appeared right after the taildrop directory picker prompt.

## When it does not apply

- The duplicate key comes from cloning a device image or restoring a backup onto a second phone; that needs key rotation, not an upgrade.
- You are on iOS, macOS, Windows, or Linux; this was an Android-only regression.
- You are already on 1.86+ and still see duplicates; investigate stale machine entries instead.

## Compatibility

- Tailscale Android app: affected in 1.84 and 1.85, fixed in 1.86 and newer.
- Tailscale admin console (any version).

## Variant phrasings

- Android showing duplicate node key after recent update
- Tailscale duplicate node key warning on Android
- taildrop duplicate machine entry Android

## Why it happens

Tailscale 1.84 added a prompt asking Android users to pick a taildrop directory at startup. Accepting it registered a second node identity for the same device, so the admin console listed two keys. In 1.86 the picker only appears when a file is actually incoming via taildrop, so no second key is created. This was maintainer-confirmed in the Tailscale issue thread.

## Edge cases

- If the Play Store has no update yet in your region, sideloading is not recommended; the duplicate entry is cosmetic until 1.86 arrives.
- Devices enrolled via MDM may need the admin to push the update.