You can’t pick what installation of Photoshop to install OnOne 9 into. Yes, I still have CS5 running, with OnOne 8 because I have certain tools that just do not work in CS6 (astronomy based actions/plugins/addons). I tried uninstalling and reinstalling v8. Still kept getting the errors. I had no way to install or keep it in just CS5 during the install. I also couldn’t pick which version of Photoshop I wanted to uninstall OnOne Suite from. ARGH!
Then another problem: after the installation, different OnOne tools that I use in conjunction because some of the features and options aren’t in the PhotoSuite, stopped working. It took about 4 hours to get that fixed, as both PhotoTune/PhotoProfessional tools had to be reinstalled, and my ‘work arounds’ applied.
I’m quite tired now.