In the Kit Kat Google changed the default permissions for writing to the external sdcard. This means that 3rd party apps no longer have access to the external sdcard. This can be especially frustrating when you are trying to manage files on your external sdcard. File Managers won't work properly. You can actually fix this problem with root access. However you should know that this is a security feature, and if you make the change it may cause OTA updates to fail. You must be rooted and you will have to edit a few text files. If none of this bothers you follow the directions in the link below to unlock writing to the external sdcard for any app.
via AndroidRevolution