From my own experience today, and as described at
https://bugs.launchpad.net/calibre/+...3?comments=all
Calibre 0.8.60 under win7 does not appear to be fully compatible with Kobo with firmware 1.9.17 or with more current firmware 2.0.0. Calibre can still transfer files to the Kobo but cannot see the Kobo database. I updated to Calibre 0.8.60 yesterday (July 17).
The error message in both cases is:
"WARNING: Failed: Kobo database version unsupported - See details
Your Kobo is running an updated firmware/database version. As Calibre has not been updated, database editing is disabled. You can enable support for your Kobo in plugin preferences. Doing so may require you to perform a factory reset. Before selecting the "Attempt to support newer firmware" option you should be familiar with restoring your Kobo to factory defaults."