Trojan Security Problem in APK

Build APK file but while installing on mobile phone produces 'Trojan' security error. I checked my computer running Debian Linux for viruses and found it clean. Is it possible your server being responsible for this problem ?

This is a false positive of your virussoftware. You could contact them they are wrong.


Thank you.

Previous builds did not produce this problem.
Which element of the app might produce this 'Trojan' safety problem ?
Could I change my app in order to fix it ?
I plan to sell it and 'Trojan' safety problems migth destroy the app.

Thank you.

Check what permissions the app expects in the app's settings.

Thank you, but it did not solve the problem.
I removed and a webViewer but still says 'Trojan' security problem.
Simple app with sound files.
I don't understand what's wrong.
And I need to sell it asap.

What was to solve the problem? I wrote you to check what permissions your app is using and let us know. If you do not understand something, write that you do not understand, and not that it does not solve the problem.

This is an issue of the Avast or AVG virus checker on your phone.

No. The only way to 'fix' the problem is to contact the distributer of the software on your phone and ask them to white list your app.
See the numerous threads that explain the issue

Avast and AVG use heuristic methods to determine if an app is malicious. It seems that shortly after App Inventor makes a major update, their software starts to falsely identify apps created with App Inventor as a Trojan. Read the or more indicate how other developers solved the 'problem'' by contacting the virus software maker.
Sorry, we can not help you. You must contact the virus software developer.


Thank you very much.
The following link provides urls to post your apk to antivirus software companies.
[ ]
I posted my apk and it had been accepted by antivirus check (in 24 hours).
Problem solved.

Ultimamente cuando instalo un .apk en el móvil aparece un aviso de posible troyano en el fichero (antes solo salia un aviso de falta de seguridad). Igualmente si envio el fichero por email, bloquea el envio por posible virus en el fichero. Esto no me ocurria anteriormente. Hay algun riesgo en instalar el .apk?

Unlikely. See the advice in post #4 and scan as indicated and make the decision yourself to gain confidence in the app you made.

What virus scanner do you have on your phone?

Avast is the scanner I have. As suggested I'm snding the file to be checked to Avast.
I'll inform about results.

It also happens to me since the last update.

  • Android 9 (Xiaomi)
  • No extensions.
  • Tested with DefaultScope: Legacy and App.
  • Simple app:


borr_vir.aia (1.5 KB)

Hello @Juan_Antonio

This is what I see when I load the apk made from your aia file on my Samsung 8.1. It is the message I always received for the past several years when installing any apk that is not sourced by the PlayStore. I have a Webroot virus checker.

I expect the message you see is generated by the built in virus checker Xiaomi supplies with their hardware which probably uses Avast. The checker is trying to protect you using heuristic methods that often fail and produce false positives.

Hopefully soon someone who has an Xiaomi and / or and Android 10 or 11 will test your simple app which compiled here fine.

I don't remember that message getting out of me in the last few months.

Maybe it's an Automatic Avast Update, (updated to 2021-09-11.)

This permission causes problems. After removing it from the manifest, Avast does not report a virus.

<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>

In my opinion, this is a bug in Avast.

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Correct @Patryk_F , I removed the permission using APK Editor Studio and now installs directly.

The funny thing is that a few weeks ago I installed correctly without having to change that permission.

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Yes, old apps that have this permission are not causing the problem. I changed the API target level to 29, the problem persisted. Perhaps something else is causing the problem. I have scanned the apps on this page:

The strange thing is that only Avast-mobile reports the virus.

I have recieved the information from Avast that my file has been checked and included in white liste. Nevertheless the problem continues when dowlanding any apk created in App Inventor. My problem is exactly the same that Juan Antonio reports. I have a Xiaomi-Redmi 6 version MIUI 11.0.4 with Avast.

Who should solve this problem?

Great :astonished:

Only Avast. I understand someone already contacted the company to get an indication of what is causing only Avast to black list App Inventor apps. They would not discuss the issue.

On your device, you could just ignore the warning (there should be a Button) and be happy :slight_smile: knowing your own apps are not causing your device harm. What you do is up to you. You might be able to disable Avast and use a different virus checker.

Also note that although it is white listed, it may take Xiaomi to access the latest Avast white list files; so if you just wait a while, the issue might self correct. :cry: