In my Kivy app I initialise some instrumentation via 3rd party .NET dlls. One of these dlls is badly behaved – takes several seconds to initialise.

To keep the app GUI responsive, I tried to initialise the instruments in a separate thread but this still results in the GUI becoming unresponsive.

I know it is this one instrument dll in particular because when I omit that instrument from the configuration the GUI remains responsive.

Also if I replace initialising each instrument with e.g. time.sleep(3) and print(instr) I see expected behaviour – init_instruments_in_background() executing and GUI remaining responsive throughout.

Am I attempting something that may be fundamentally not possible? Can it be that this 3rd party dll is just not capable of running in a separate thread without blocking the main thread? I think the reason for the slow execution of this dll is a TCP/IP telnet comms timeout delay. The OS is Windows 10. Python 3.12.4, Kivy 2.3.0

in main widget in kivy gui

def init_instruments_in_background(self):

    #instruments are classes defined in Instrument1.py, Instrument2.py, etc
    for instr in ['Instrument1', 'Instrument2', 'Instrument3']:
        globals()[instr] = __import__(instr)
        #THIS OPERATION BLOCKS THE MAIN THREAD IN THE CASE OF ONE INSTRUMENT
        self.Instruments[instr] = globals()[instr].Instrument(<ip_addr>, <port>)

def init_instruments(self):
    equip_thread = Thread(target=self.init_instruments_in_background, daemon=True)
    equip_thread.start()

self.init_instruments()

structure of InstrumentX.py classes

import clr 
class Instrument:

    def __new__(self, ip_addr, port):

        clr.AddReference('<name_of_.NET_instrument_driver_dll>')
        from <NET_instrument_driver_namespace> import InstumentX
        self.INTERFACE = InstrumentX(ip_addr, port)

        return self.INTERFACE