Thank you: that did the trick!
When/if we all migrate to AutoDesSys, I hope the same community of benevolent advice persists. I really appreciate the help.
patrick
Migration
Re: Migration
I finally got my iMac up and running on Sierra again. It turned out that my problem (kernel panics) was not some corrupt system file but a damaged hard disk. When I took it into the Apple Store, they anticipated replacing the RAM and logic board. Instead, they replaced the hard disk. After it was up and running, I tried reinstalling software, but kept running into roadblocks. (My MS Office 2016 is can no longer be registered, so there was no way to save an Excel file. My versions of SketchUp predate their current subscription model, so there was no way to activate them.) After much frustration, I erased the disk, reinstalled Sierra from recovery mode, then used Migration Assistant to move everything from a SuperDuper clone to the reformatted computer. Man, what a relief to be up and running and in my old paradigm, with all my PC9 key commands working, SketchUp working, iWork 09 working, and fortunately, I still had Office 2008 on the clone, so I'll use that instead of Office 2016. The only drawback is that I lost my BootCamp partition, so I'll have to reinstall Windows again. Fortunately, I only use Simpson Strong-Tie epoxy anchor software (which is free), so I'll only lose time with that reinstall.