Jim, something must be wrong with your macs. I haven't heard of one OS or hardware problem (outside of Archicad and it's companions) caused by the installation of AC10, despite that the beta testers installed several versions of AC10 one after another. And the early ones had some significant bugs.
But of course, the usual safety precautions should be taken, as with any heavy program installation and system update:
- Upgrade to latest stable system release (check with MacFixit before installing Apple's fresh software updates)
- Full backups (i recommend SuperDuper)
- Repair permissions before AND after installation (especially Microsoft and Adobe tend to screw things up)
AC4.1-AC26SWE; MacOS13.5.1; MP5,1+MBP16,1