[轉]Android app has error: Execution failed task':app:preDexDebug' trying to test parse but can't run app with this error 六月 7, 2015 https://teamtreehouse.com/forum/android-app-has-error-execution-failed-taskapppredexdebug-trying-to-test-parse-but-cant-run-app-with-this-error http://stackoverflow.com/questions/25529155/android-studio-gradle-error-predexdebug Try this : File —-> Invalidate caches/restart