Proguard error: "Exception while processing task Please correct the above warnings first"

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Since upgrading to android gradle plugin 3.0.1 I am getting following error:

Warning: Exception while processing task Please correct the above warnings first.

:app:transformClassesAndResourcesWithProguardForProductionRelease FAILED

Problem is: I don't see any warning in my log.

I also ran the build with -i flag and I am getting following (big) log:

Any ideas are very welcome!

This is because in your dependencies there are multiples rxjava implicit dependencies with different version.

From this log:

Reading program jar [/Users/steph/.gradle/caches/modules-2/files-2.1/io.reactivex/rxjava/1.2.5/b423532b5a3c949cbb799468f83bf566032fe98d/rxjava-1.2.5.jar] (filtered)


Reading library jar [/Users/steph/.gradle/caches/modules-2/files-2.1/io.reactivex/rxjava/1.2.3/7fe1a94c1aeb958acc876fe616922cc191f3222c/rxjava-1.2.3.jar] (filtered)

You can see that in your app, there is 2 version of rxjava: 1.2.3 and 1.2.5

One of your dependencies, android-rxlocationsettings, is using rxjava 1.2.5, you can take a look at its build.gradle:

apply plugin: ''

dependencies {
  compile ''
  compile ''
  compile ''
  compile 'io.reactivex:rxjava:1.2.5'

android {
  compileSdkVersion 25
  buildToolsVersion "25.0.2"

  defaultConfig {
    minSdkVersion 14

So, you need to exclude it either using exclude from dependency:

dependencies {
  compile ('com.github.jetradarmobile:android-rxlocationsettings:1.1.0') {
    exclude group: "io.reactivex", name: "rxjava"

or using configuration:

configurations.all {
    exclude group: "io.reactivex", module:"rxjava"

ProGuard icon ProGuard manual, InvalidClassException, class loading error, or verification error (in Java Micro Edition). Error: No Such Field or Method, Error verifying method (in a Java Micro  Xamarin has built-in support for Proguard. However, you may run into following error when you enable Proguard. Proguard error ‘C:\Program Files (Access is Denied)’ This is caused by a space in the path for Android-SDK location (which is where Proguard resides).

The only thing that worked for me was this answer by @Moti Bartov


At the end of

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just use -dontwarn in like below

-dontwarn com.

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I had a similar issue, in my case I checked the logs for warnings if you find any related to class reference, it indicates you need to clean build the project.

run gradlew clean followed by

gradlew build

or combined gradlew clean build

Build Failed

Warnings to look out for

Android release build crashes with proguard error · Issue #25951 , Proguard error after upgrating stable to v1.9.1+hotfix.2 #40168. Closed. yaymalaga opened this issue on Sep 10, 2019 · 21 comments. Closed  Yes, it works without ProGuard. Besides, it also works with ProGuard while not linking. I'm not using a custom ProGuard config, so I use the one bundled with the Xamarin.Android SDK ( See below. I wanted to use ProGuard because it is beneficial for size and performance of the app. The other consideration to use ProGuard is because of

try this (it's work for me)

I have also issue with pro guard but i found following code from git hub more useful.

add this line on


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  • You should run your build with the -i flag and add -verbose to your proguard rules to get more output. The warning should be printed right after reading the library which has the problem.
  • can you please also add how you found out about the conflict?
  • @stoefln: you can found it from Note: duplicate definition of library class [rx.BackpressureOverflow$Strategy]. rx.*** is part of rxjava. Btw, you also have another duplicate library, it's probably android httpclient. every line with Note: duplicate definition of library class is telling you that you have duplicate dependencies whether explicitly or implicitly.
  • Thanks, makes sense. And how did you find out which libraries are referencing rx?
  • It's simple, if you try founding for rx. occurances in your log, you will found out something like this: Note: duplicate definition of library class [rx.plugins.RxJava.**. Which means rx.** is the package of rxjava. Then go to the rxjava github to make sure. There you will found out that the package is for rxjava version 1.
  • Yes, you're correct. You can use ./gradlew app:dependencies to see the dependencies tree. Or you can get a quick glance of your dependencies tree in your project by selecting the Project toolbar on the left then change Android to Project. You can see the library from External Libraries.