[kaulad]

I am a new user in Linux and seem to be groping in a vast unlighted cave system.

I found out how to disable mount. At least, hunar doesn't pop up with file display.
I then restarted system.
Calibre cannot see device.

Ran Calibre in debug mode, obtained log.

Spoiler:

Using calibre Qt style: True
libusb_claim_interface() reports device is busy, likely in use by GVFS or KDE MTP device handling alreadyLIBMTP PANIC: Unable to initialize device
Traceback (most recent call last):
File "calibre/devices/mtp/unix/driver.py", line 214, in open
File "calibre/devices/mtp/base.py", line 24, in synchronizer
File "calibre/devices/mtp/unix/driver.py", line 166, in create_device
libmtp.MTPError: Unable to open MTP device with busnum=3 and devnum=2, tried 1 such devices

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "calibre/gui2/device.py", line 325, in detect_device
File "calibre/devices/mtp/driver.py", line 127, in open
File "calibre/devices/mtp/base.py", line 24, in synchronizer
File "calibre/devices/mtp/unix/driver.py", line 217, in open
calibre.devices.errors.OpenFailed: Failed to open MTPDevice(busnum=3, devnum=2, vendor_id=6473, product_id=1505, bcd=547, serial='G001LT0620170MXD', manufacturer='Amazon', product='Fire'): Error: Unable to open MTP device with busnum=3 and devnum=2, tried 1 such devices
calibre Debug log
calibre 6.9 embedded-python: True
Linux-5.15.0-53-generic-x86_64-with-glibc2.35 Linux ('64bit', 'ELF')
('Linux', '5.15.0-53-generic', '#59-Ubuntu SMP Mon Oct 17 18:53:30 UTC 2022')
Python 3.10.1
Interface language: None
calibre 6.9 embedded-python: True
Linux-5.15.0-53-generic-x86_64-with-glibc2.35 Linux ('64bit', 'ELF')
('Linux', '5.15.0-53-generic', '#59-Ubuntu SMP Mon Oct 17 18:53:30 UTC 2022')
Python 3.10.1
Interface language: None
QPA platform: xcb
devicePixelRatio: 1.1979166666666667
logicalDpi: 96.0 x 96.0
physicalDpi: 76.66638418079096 x 76.7105527638191
[0.00] Starting up...
[0.00] Showing splash screen...
[0.05] splash screen shown
[0.05] Initializing db...
[0.06] db initialized
[0.06] Constructing main UI...
Screens currently in system:
{'depth': 24,
'device_pixel_ratio': 1.1979166666666667,
'geometry_in_logical_pixels': {'height': 1202, 'width': 2137, 'x': 0, 'y': 0},
'index_in_screens_list': 0,
'manufacturer': 'Samsung Electric Company',
'model': 'S32D850-',
'name': 'DVI-I-1',
'serial': 'HTPHB00735-',
'size_in_logical_pixels': {'height': 1202, 'width': 2137},
'virtual_geometry': {'height': 1202, 'width': 4697, 'x': 0, 'y': 0}}
{'depth': 24,
'device_pixel_ratio': 1.1979166666666667,
'geometry_in_logical_pixels': {'height': 1202,
'width': 2137,
'x': 2560,
'y': 0},
'index_in_screens_list': 1,
'manufacturer': 'Samsung Electric Company',
'model': 'S32D850-',
'name': 'DVI-I-2',
'serial': 'HCHNA01020-',
'size_in_logical_pixels': {'height': 1202, 'width': 2137},
'virtual_geometry': {'height': 1202, 'width': 4697, 'x': 0, 'y': 0}}
Error while trying to open MTPDevice(busnum=3, devnum=2, vendor_id=6473, product_id=1505, bcd=547, serial='G001LT0620170MXD', manufacturer='Amazon', product='Fire') (Driver: <calibre.devices.mtp.driver.MTP_DEVICE object at 0x7fabe89fadd0>)
Restoring geometry for: calibre_main_window_geometry
{'frame_geometry': {'height': 1202, 'width': 2137, 'x': 2560, 'y': 0},
'full_screened': False,
'geometry': {'height': 1179, 'width': 2137, 'x': 2560, 'y': 23},
'maximized': True,
'normal_geometry': {'height': 1046, 'width': 1909, 'x': 2564, 'y': 33},
'screen': {'depth': 24,
'device_pixel_ratio': 1.1979166666666667,
'geometry_in_logical_pixels': {'height': 1202,
'width': 2137,
'x': 2560,
'y': 0},
'index_in_screens_list': 1,
'manufacturer': 'Samsung Electric Company',
'model': 'S32D850-',
'name': 'DVI-I-2',
'serial': 'HCHNA01020-',
'size_in_logical_pixels': {'height': 1202, 'width': 2137},
'virtual_geometry': {'height': 1202,
'width': 4697,
'x': 0,
'y': 0}}}
Matching screen: {'depth': 24,
'device_pixel_ratio': 1.1979166666666667,
'geometry_in_logical_pixels': {'height': 1202,
'width': 2137,
'x': 2560,
'y': 0},
'index_in_screens_list': 1,
'manufacturer': 'Samsung Electric Company',
'model': 'S32D850-',
'name': 'DVI-I-2',
'serial': 'HCHNA01020-',
'size_in_logical_pixels': {'height': 1202, 'width': 2137},
'virtual_geometry': {'height': 1202, 'width': 4697, 'x': 0, 'y': 0}}
Moving widget to saved screen
Setting widget geometry to: {'height': 1179, 'width': 2137, 'x': 2560, 'y': 23}
Restoring widget to maximized
[0.53] main UI initialized...
[0.53] Hiding splash screen
Starting QuickView
[7.88] splash screen hidden
[7.88] Started up in 7.88 seconds with 0 books
Saving geometry for: calibre_main_window_geometry
{'frame_geometry': {'height': 1202, 'width': 2137, 'x': 2560, 'y': 0},
'full_screened': False,
'geometry': {'height': 1179, 'width': 2137, 'x': 2560, 'y': 23},
'maximized': True,
'normal_geometry': {'height': 1179, 'width': 2137, 'x': 2560, 'y': 23},
'screen': {'depth': 24,
'device_pixel_ratio': 1.1979166666666667,
'geometry_in_logical_pixels': {'height': 1202,
'width': 2137,
'x': 2560,
'y': 0},
'index_in_screens_list': 1,
'manufacturer': 'Samsung Electric Company',
'model': 'S32D850-',
'name': 'DVI-I-2',
'serial': 'HCHNA01020-',
'size_in_logical_pixels': {'height': 1202, 'width': 2137},
'virtual_geometry': {'height': 1202,
'width': 4697,
'x': 0,
'y': 0}}}
Device 0 (VID=1949 and PID=05e1) is a Amazon Kindle Fire 10 Plus.

If someone could 'explain like I was 5', I would appreciate it.