You might want to update using the safe mode to fix this
First boot your Mac in the safe mode
- On your Mac, choose Apple menu > Shut Down.
- 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.
- Press and hold the power button on your Mac until “Loading startup options” appears.
- Select a volume.
- Press and hold the Shift key, then click Continue in Safe Mode.
- The computer restarts automatically. When the login window appears, you should see “Safe Boot” in the menu bar.
When booted into the safe mode, go to system settings>general>software update like you usually do when trying to update. See if the update will continue this way.