You may see an error like the following while trying to delete a directory in the cPanel File Manager.
FileOp Failure On: /home/user/public_html/folder Directory not empty.
This can be caused by the directory containing a file or directory that is owned by a different user, or a file or directory that is write protected.
Ensure that the directory and all of its contents are owned by the cPanel user. The following example command will change ownership of a file or directory the user where USER is the cPanel user accessing the file manager, and /PATH/TO/FILEORDIRECTORY is the full path to the file or directory.
chown USER:USER /PATH/TO/FILEORDIRECTORY
Ensure that the directory and its contents are all writeable to the cPanel user. Typically directories will have 755 permissions and files will have 644 permissions. The following example commands will change the permissions on a file or directory where /PATH/TO/FILE and /PATH/TO/DIRECTORY are the full paths to the file or directory.
chmod 755 /PATH/TO/DIRECTORY
chmod 644 /PATH/TO/FILE