That error means your device is being opened by the desktop environmnet/file manager. Prevent it from being auto-mounted and you will be fine. On Linux, only one program can talk to an MTP based device at a time.
** Changed in: calibre Status: Confirmed => Invalid -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1797890 Title: Enhancement-Kindle fire HD 8 To manage notifications about this bug go to: https://bugs.launchpad.net/calibre/+bug/1797890/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs