Answer : Ok, I was finally able to figure out the reason. The problem was, that my project folder resided on a different hard disk partition, than my home folder. The folder containing my android projects was linked to my home folder with a symbolic link. I can't tell whether its the symbolic link, or the other partition, that is causing the problem. I haven't checked that. Maybe it works if you have it on the same partition but linked with a symbolic link. Maybe it works when used on another partition without symbolic links. But for anyone experiencing this problem -> Check if one of these might be your cause as well. Some extra information: My android project folder resided on a hard disk partition formatted with ZFS. I saw a version of this with just now on Android Studio 3.4: the only error message I saw in the IDE was that Gradle sync failed, but in idea.log there was a NullPointerException and its traceback originated at com.intellij.openapi.extensions.Exte