Gradle clean task fails in gradle [version 5.6.4 and 6.0.1]

The first thing to try is using the simplest command possible ./gradlew clean from the root project. If that doesn’t work try stopping all daemons with ./gradlew --stop becore cleaning. If that doesn’t work, you should look at your environment to ensure you don’t have any configuration that may cause failures. In your scenario, something seems to be locking the build directory. Looking at the lock held using something like Process Explorer from Sysinternal can help. Finally, make sure you don’t have any code that may be using the build directory as a permanent workspace. Gradle should be the only one writing to the directory.