Rh 6 hangs when changing units in complex models

RH 6 is having issues when I change the units using the Units command. I select inches (from feet) and it prompts whether to scale the model. I select yes, and it scales some stuff but then hangs on “Updating settings…:”

Some geometry gets scaled, but the majority does not. Rhino sits for 5, 7, 10+ minutes with nothing changing in the model. I can change the window, pan and zoom, switch toolbars, but the window can’t close and command can’t be interrupted or cancelled. I have to end process in Task Manager and rhino does not recognize a crash.

Question: does Units scaling override layer locked/hidden and scale all objects in the file regardless of lock/unlock, hide/show, layer state? I hope yes, but would like clarification.

Yes, that is correct.

You might try downloading the evaluation version of V7 and see if the same problem occurs. If not, then it is a bug that has been fixed. If it does happen also in V7, then you could upload the file to McNeel via their uploads page for testing.