FAQ Section: Build Errors

[ABG]

apk Install Errors

Google Play Protect Unsafe App Blocked - @Anke

Build Errors

[PrepareAppIcon] Task errored - @Boban

[PrepareAppIcon] Task errored - @TimAI2

[ReadBuildInfo] Task Errored - (Project inside project) - ABG

Naming a button 'back' or 'take' causes build errors - @Boban

apkSigner execution failed - SteveJG

Build Server Status - MIT

Build Servers Overview Bar Graph app - ABG

nb184 - Compiling error:

SteveJG's Monster List of Build Errors

Build app QR code regularly stops at 30% compiling part 1

App Inventor is unable to compile this project.” Error may be caused by: → Project in a project (extension) - Anke

Spaces in Project name cause build errors - ewpatton

d8 Errors

Error d8 failed

Reduce your block count: Use parametrized procedures for common code Use Media text files instead of big clumps of text blocks Use generic blocks instead of repeating component event blocks Encode repeating decision patterns into lookup tables loaded from Media csv text files (does your blocks image look like a box of combs?) You don't need a component for every data instance. Reuse those components. If you can't fit data into a ListView or List Picker, show a small subset of the data in an A…

"ERROR: d8 failed" while trying to build app, using AdvancedBarcodeScanner extension by Ken Nichols

thanks for support. I changed AdvancedBarcodeScanner extension created by Ken Nichols to inbuilt 'Component for using the Barcode Scanner to read a barcode' and then apk is downloaded. i wanted to try advance as some time inbuilt was failing so. but didn't get it why its failed.

DX Errors

RunMultidex ERROR: DX returned an error code (extensions) - @Taifun

RunMultidex ERROR: DX returned an error code (block limit) - @ewpatton

[RunAapt] ERROR: Error running AAPT

Unable to compile the project, AAPT execution failed

I'm not sure how you've done this, but your project name contains spaces. The project name dialog typically prevents this from happening. Try saving your project using the Save As menu item and rename the project so it doesn't contain spaces and try again. Spaces in the project name will generate invalid code that won't compile.

Media file name about:blank - @Boban

Quote mark in version string - @Orange_Gumdrop Aug 2025

XML SAXParseException

NotePad++ Navigation Techniques - @Boban

YAIL compiler - AAPT execution failed errors ...

Copied Screen Names Don't Match - @Boban

Media file named Location.png - @Ramon, @Boban

multiple assets with the same name (after downshift)- Boban

Quick way to find duplicate Assets files - @Boban

multiple assets with similar names except for case - ABG

'@' in Appname - @Boban

Appname = ???

'<' in AppName - @Mr_Czechowski Sep 2025

Quotes in app name - @Boban

Use shorter name for your images and also no extra dot in names - @Boban

Runitime Errors in Built Apps

Runtime error: Attempt to invoke virtual method ‘Java .lang.class java.lang.object.getclass()’ on a null object reference

Workarounds

Unable to insert '&' in app name - @Anke