Unable to connect to the filesystem. Please confirm your credentials
I also had this issue. Solution is go to applications/xampp/htdocs and right click on the wordpress folder on which you are trying to install plug-in or theme. click get info, scroll to bottom, click on the lock to unlock it and type in your password and enter, in sharing and permissions allow privilege to system,admin and everyone and click on the setting icon in bottom left and apply to enclosed items.