[dmp1991]

Well, having the problem again with the latest version of Calibre (3.31.0) and now rebooting the phone doesn't fix it. I've tried deleting the files driveinfo.calibre and metadata.calibre again. I've rebooted the phone, restarted Calibre, and then tried to connect again -- same problem.

Here's the error message:

calibre, version 3.31.0
ERROR: Error: Error communicating with device

Failed to upload file named: driveinfo.calibre to (u'Internal shared storage',): 2:PTP Layer error 2008: send_file_object_info(): Could not send object info.
2:Error 2008: PTP: Invalid Storage ID

Traceback (most recent call last):
File "site-packages/calibre/gui2/device.py", line 87, in run
File "site-packages/calibre/gui2/device.py", line 510, in _books
File "site-packages/calibre/devices/mtp/driver.py", line 218, in books
File "site-packages/calibre/devices/mtp/driver.py", line 190, in get_driveinfo
File "site-packages/calibre/devices/mtp/driver.py", line 180, in _update_drive_info
File "site-packages/calibre/devices/mtp/driver.py", line 151, in put_calibre_file
File "site-packages/calibre/devices/mtp/base.py", line 26, in synchronizer
File "site-packages/calibre/devices/mtp/unix/driver.py", line 403, in put_file
DeviceError: Failed to upload file named: driveinfo.calibre to (u'Internal shared storage',): 2:PTP Layer error 2008: send_file_object_info(): Could not send object info.
2:Error 2008: PTP: Invalid Storage ID

Not sure why it's complaining about PTP, it looks to be using the MTP Device Interface 1.0.0 plugin, at least my device info shows up under that plugin's configuration page.

Pixel
Serial number: ...
Manufacturer: Google
Model: Pixel
ids: (20, 21, 6353, 20193, u'...')
Device version: 1.0
Storage:
[{'capacity': 120574005248L,
'freespace_bytes': 83889422336L,
'freespace_objects': 1073741824L,
'id': 65537,
'name': 'Internal shared storage',
'removable': False,
'rw': True,
'volume_id': None}]