USB stuck on ‘Loading’ and finder stops responding

Hi Aary_D,

Thanks for posting here in Apple Communities. Do you have any other devices connected to your Mac? If so, remove them and try connecting the USB again. You'll also want to restart your Mac since this can sometimes address the issue you're facing. You can see what to do if your USB won't work with your Mac. See: If a USB device doesn’t work with Mac - Apple Support

If you're still having an issue you can test out your Mac in safe mode: Start up your Mac in safe mode - Apple Support

"Start up your Mac with Apple silicon in safe mode

1. On your Mac, choose Apple menu  > Shut Down.
2. Wait for your Mac to shut down completely. A Mac is completely shut down when the screen is black and any lights (including in the Touch Bar) are off.
3. Press and hold the power button on your Mac until “Loading startup options” appears.
4. Select a volume.
5. Press and hold the Shift key, then click Continue in Safe Mode.
6. The computer restarts automatically. When the login window appears, you should see “Safe Boot” in the menu bar.

Start up your Intel-based Mac in safe mode

1. Turn on or restart your Mac, then immediately press and hold the Shift key until you see the login window.
2. Log in to your Mac.
3. You might be asked to log in again.

On either the first or second login window, you should see “Safe Boot” in the menu bar."

Kind regards.