Thanks, this is starting to look like what Obama & Merkel would call an "off ramp" option
Waiting for time machine to back up everything before attempting to install my old DVD copy of OS X 10.6 on an external HD hooked up to my wife´s late-2011 Macbook Pro, I reread the CaptureShop 6.1.2 Readme pdf file that comes with the download including this note with my emphasis in green on stability:
There is the possibility that on some computers permanent Firewire usage, i.e. use of Live
Image, can lead to crashes with Captureshop. From our experience most computers operating
under Mac Os 10.5.x are affected. Running CaptureShop with Mac OS 10.4.11 or 10.6.8 and
higher on the same computer performs stable.
In general we recommend to operate computers with G5 processors under Mac OS 10.4.11
and Mac OS 10.6.8 on computers with Intel Processors.
If you do not experience such crashes with your configuration, there is no need to upgrade or
downgrade, though.
I am not using Live Image or permanent firewire, and in my case the instability occurs on a computer "running 10.6.8 and higher" also when trying to download from CF card rather than firewire, but I am also not deaf and dumb ie looks like 10.6.8 maybe the way to go on computers with Intel processors?