Android Studio 3.0 Execution failed for task: unable to merge dex

Question

android studio was getting build error while build execution with following:

Error:Execution failed for task \':app:transformDexArchiveWithExternalLi

Answer 1

I was receiving the same error and in my case, the error was resolved when I fixed a build error which was associated with a different build variant than the one I was currently building.

I was building the build variant I was looking at just fine with no errors, but attempting to debug caused a app:transformDexArchiveWithExternalLibsDexMergerForDebug error. Once I switched to build the other build variant, I caught my error in the build process and fixed it. This seemed to resolve my app:transformDexArchiveWithExternalLibsDexMergerForDebug issue for all build variants.

Note that this error wasn't within the referenced external module but within a distinct source set of a build variant which referenced an external module. Hope that's helpful to someone who may be seeing the same case as me!