SKU Pro 18 freezing when I try to delete a layer in layer window

Working in SKU Pro (v 18.1.1180) on a Mac (v.10.15.5) and I have a number of currently empty and useless layers in my model. When attempting to delete any one of these layers from within the layer window I get the spinning beach ball of death and am forced to quit. I don’t believe I’ve encountered this before. Any thoughts?

If the layers are unused, what happens if you purge unused layers instead of trying to delete them?

That totally worked. Thanks.

Good. While you’re purging stuff, you might want to use Window>Model Info>Statistics>Purge Unused.