diff --git a/src/calibre/devices/usbms/device.py b/src/calibre/devices/usbms/device.py index 8072cd4874..e852ae7f62 100644 --- a/src/calibre/devices/usbms/device.py +++ b/src/calibre/devices/usbms/device.py @@ -260,7 +260,8 @@ class Device(DeviceConfig, DevicePlugin): # if the device is connected without a card, the above # will incorrectly identify the main mem as carda # See for example the driver for the Nook - if 'main' not in drives and 'carda' in drives: + if drives.get('carda', None) is not None and \ + drives.get('main', None) is None: drives['main'] = drives.pop('carda') drives = self.windows_open_callback(drives)