Error communicating with device

Suddenly I'm having trouble connecting my kindle paperwhite to calibre. Here's the error I receive. Any ideas?

[Errno 22] Invalid argument: 'D:\\metadata.calibre'

Traceback (most recent call last):
File "calibre\gui2\device.py", line 87, in run
File "calibre\gui2\device.py", line 548, in _books
File "calibre\devices\kindle\driver.py", line 432, in books
File "calibre\devices\usbms\driver.py", line 313, in books
File "calibre\devices\usbms\driver.py", line 466, in sync_booklists
File "calibre\devices\usbms\driver.py", line 463, in write_prefix
OSError: [Errno 22] Invalid argument: 'D:\\metadata.calibre'