To Solve Not Able To Open Device Manager in Android Studio Error Just You need to Follow this Step to Open Device Manager. First of all click left in file tree on the root node (Your project name). Then Selecr MENU Select FILE Then Select PROJECT STRUCTURE. Select left MODULES. hit + button to add ANDROID. hit OK Button. top of the root node (project name) select PROJECT. Now you can see your old view. Now, Your error must be solved.