From times in times, when I unlock my screen comes up an automatic installation attempt, blocked by my settings (block from unknown sources). I would like to know if this app, called Calculator Exchange is a safe one to install.

KitKat 4.4.2 Z4

Thanks a lot in advance.

Sandro Vieira


2 Answers 2


If an app prompts always, it is not safe to install.

It is an ad by any of the app in your phone and it may or may not be a malicious app.

If that app is from playstore, it is less vulnerable but it is directly from an apk. So it is highly vulnerable.

Go to filemanager, search by possible keywords, find and delete the apk file.


Your device might be infected with virus that is actually trying to install the app Calculator Exchange. So I strongly recommend you to take backup of you data such as contacts,photos,videos,etc., and Reset your device to Factory settings

  • Android doesn't have virus, but malware. If the malware resides in the /system partition, a factory reset won't help.
    – Grimoire
    Mar 14, 2017 at 12:00
  • For that we need to hard reset the device. Mar 14, 2017 at 13:04
  • Incorrect. To remove a malware located in /system, you need to reflash the firmware.
    – Grimoire
    Mar 14, 2017 at 13:06

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