ColorSoft && Mac Error

Trying to use my Kindle color soft with Calibre -- this is the error I get when I plug in the kindle (on Mac).

Failed to upload file named: metadata.calibre to ('Internal Storage',): 2:PTP Layer error 02ff: send_file_object_info():Could not send object property list.

2:Error 02ff: PTP I/O Error

Traceback (most recent call last):

File "calibre/gui2/device.py", line 111, in run
File "calibre/gui2/device.py", line 582, in _books
File "calibre/devices/mtp/driver.py", line 345, in books
File "calibre/devices/mtp/driver.py", line 386, in write_metadata_cache
File "calibre/devices/mtp/driver.py", line 211, in put_calibre_file
File "calibre/devices/mtp/base.py", line 24, in synchronizer
File "calibre/devices/mtp/unix/driver.py", line 403, in put_file

calibre.devices.errors.DeviceError: Failed to upload file named: metadata.calibre to ('Internal Storage',): 2:PTP Layer error 02ff: send_file_object_info():Could not send object property list.

2:Error 02ff: PTP I/O Error

How do I fix this?