We're sorry about the trouble with Lightroom Classic. Would you mind confirming the version of Lightroom Classic you updated to? Are the images you're trying to delete on an external drive?
You can try launching Lightroom Classic as administrator by right clicking on the icon and selecting the option to Run as Administrator to check if that helps. If the issue persists, you can try to reset the preferences of Lightroom using the steps mentioned here: https://adobe.ly/2JSym5e
Please backup your presets prior to resetting the preferences.