ThreaadingViolation when the button "Change anallyzed folder" is pressed

[Edoardo Barolo]

Hello, I have the latest version (7.12.0) on Windows 11.

I plugged my cellphone into the USB and enabled USB File Transfer. Calibre detects both my internal memory and my SD card. I have ebooks in a different folder, so I clicked the "Configure device" button and accessed the menu. I then clicked on "Change the directory to be analyzed" (I have the Italian version, so this might be worded differently).

After that, I received an error popup saying:

calibre, version 7.12.0
ERRORE: Eccezione non gestita: <b>ThreadingViolation</b>:

You cannot use the MTP driver from a thread other than the thread in which startup() was called

calibre 7.12 embedded-python: True
Windows-10-10.0.22631-SP0 Windows ('64bit', 'WindowsPE')
('Windows', '10', '10.0.22631')
Python 3.11.5
Windows: ('10', '10.0.22631', 'SP0', 'Multiprocessor Free')
Interface language: it
EXE path: C:\Program Files\Calibre2\calibre.exe
Successfully initialized third party plugins: Extract ISBN (1, 6, 3)
Traceback (most recent call last):
  File "calibre\gui2\device_drivers\mtp_config.py", line 453, in change_ignored_folders
  File "calibre\gui2\device_drivers\mtp_folder_browser.py", line 118, in __init__
  File "calibre\devices\mtp\windows\driver.py", line 258, in filesystem_cache
  File "calibre\devices\mtp\windows\driver.py", line 36, in check_thread
calibre.devices.mtp.windows.driver.ThreadingViolation: You cannot use the MTP driver from a thread other than the thread in which startup() was called

[Kovid Goyal (kovid)]

I am travelling for a week so cant look at hardware related issues, but
when I return I will investigate. Although I dont have any MTP devices
that support SD cards, so if the issue is specific to that it might not
be fixable by me. In the meantime as a workaround you can eject the sd
card from the device and use an sd card reader and the "connect to
folder" function in calibre to send books to it.

[Kovid Goyal (kovid)]

Doesnt reproduce for me. However I dont have an MTP device with an SD
card to test with, though I dont see why that should make any diffrence
to this error. Does it still happen for you if you first remove the SD
card?