After a recent update an error pops up at exit. 
I’ve seen several other posts with similar errors. Any advice on how to finally solve this?
Hi Benjamin- you need to put that RUI file in another, writable, location. Peter’s tools were created back in the dim past when it was OK to write to the program files folders, but that is no longer allowed.
-Pascal
Thanks, Pascal. I’ll try that. So do you suggest moving all of the rhino plugins (paneling tools, rhino nest, section tools, etc.) to another folder? I’m a bit surprised that this is the only one giving me any trouble.
+b
No, only the files that the user can modify, like the RUI toolbars. The other plug-in files you mentioned are not modified by use like the RUI file is.
Files like default.rui that are designed to be user modified are stored in the user’s Roaming profile folder.
Thanks for the clarification, John.