# Resolve APK Signature Conflict

### Error Explanation:

"An existing package by the same name with a conflicting signature is already installed", this error occurs during APK installation on Android systems for smart POS devices. It indicates a signature conflict with an already installed package of the same name. There are three primary reasons for this error:

1. Duplicate Package with Different Signature: A different APK with the same package name but a different signature is already installed on the device.
2. Unsigned APK: The APK you are attempting to install has not been signed.
3. Invalid Signature: The APK is signed, but the signature is either a debug key or it's not authenticated by the terminal's root certificate.

### Resolution Steps:

1. For the First Reason:
   * Remove the previously installed APK.
   * Then attempt to install the new APK.
2. For the Second and Third Reasons:
   * Obtain a valid certificate from WizarPOS.
   * For detailed instructions, refer to the guide on [How to Apply App Certificates](http://sdkwiki.wizarpos.com/index.php/How_to_apply_app_certificate).
3. Verifying Your Keystore:

   * Run the command: keytool '-list -keystore xxxx.jks -v'.
   * Ensure the keystore includes a certificate issued by the terminal owner (default is WizarPOS). For example, a certificate from WizarPOS should have the issuer details like "EMAILADDRESS=<support@wizarpos.com>, CN=releasetestv1, OU=Testing, O=wizarpos, L=Shanghai, ST=Shanghai, C=CN"
   *

   ```
   <div align="left"><figure><img src="/files/6Jz27gLT7olCEu9lwT5h" alt=""><figcaption></figcaption></figure></div>
   ```
4. Checking the Alias Name of the Private Key:
   * If multiple private keys exist in your keystore, ensure you select the one that pairs with the certificate you applied for.

### Important Notice:

When using an Integrated Development Environment (IDE) tool to sign your app, avoid using the default IDE keystore. Always use a custom keystore for which you have obtained a certified signature.


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://smartpossdk.gitbook.io/cloudpossdk/faq/other-development/resolve-apk-signature-conflict.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.