[simonb]

I have used calibre successfully about a month ago. When I came back today to send more books to my device I get the following error message.

(21, 'GetDiskFreeSpace', 'The device is not ready.')

Traceback (most recent call last):
File "site-packages\calibre\gui2\device.py", line 82, in run
File "site-packages\calibre\gui2\device.py", line 412, in _upload_books
File "site-packages\calibre\devices\usbms\driver.py", line 256, in upload_books
File "site-packages\calibre\devices\usbms\device.py", line 1010, in _sanity_check
File "site-packages\calibre\devices\usbms\device.py", line 175, in free_space
File "site-packages\calibre\devices\usbms\device.py", line 138, in _windows_space
error: (21, 'GetDiskFreeSpace', 'The device is not ready.')

I have tried uninstalling and reinstalling calibre, going back to the version previously used, using different USB port, charging and restarting Kindle. Can download from Amazon with USB. Any advice appreciated. Be aware I am computer novice. I have Windows 7 Home Premium.