1) Download the SDK platform for API 20 (4.4W) 2) Navigate to your sdk folder (should be like D:\EclipseWorkspace\adt-bundle-windows-x86_64-20140321\sdk) 3) Go to platforms folder -> android-21 folder -> data folder 4) rename layoutlib.jar (for backup purpose) 5) copy the same file from your android-20 folder to this folder 6) restart Eclipse