Android OS version kitkat (ver 4.4) since occurred. For external SdCard such as copying and deleting.
Trying to solve it, but seems to take a long time.
Temporarily, File Explorer menu at the top [External Sd Card] button to set the connection.
Accessible path to the subdirectory of SdCard.
For this area, the file copy, delete, etc. are supported.
(This statement is made kitkat OS users only.)
● Explorer (File Manager)
○ Introducing the top menu
Go to the top of the Root Path of smart devices.
Go to the top path of external storage space on the SD card.
Move to the top of the folder.
Move to the previous folder. (The same equipment and features of the Back button)
Go to the location, cameras and video files are saved .
Go to the location, downloaded files are stored on the Internet
Refresh the page.
▷ RESET SEARCH
Search mode when the button is activated. Button is pressed, the search is initiated.
Smart File Manager application is the File Explorer for Android.Multi-select feature has been improved.
It's simple and effective. I'd even say it was intuitive as I rarely use it but find it easy to use when I do.