Some updates: I could install CC (and iClone) without issue on my secondary system, which is cleaner because it is never used for testing. So I decided to do a fresh install of CC as follows: 1. Completely uninstalled CC3.4 and also Smart Gallery for CC. 2. Renamed existing CC Template folder to force creation of a new one on reinstall. 3. Used script to reset the SG database (as provided for CC 3.3 beta testing). (I think I rebooted at this point.) 4. Reinstalled CC 3.4, but not yet SG. 5. Result: New hair content can be accessed in Content Manager. 6. Closed CC and installed Smart Gallery. 7. Launched CC, and waited for SG to sync. 8. Result: New hair content can still be accessed in Content Manager. 9. Install free content in SG (as a first step). 10. Hair content can still be selected in CM without issue. 11. Hair content selected in SG can be shown in CM and vice versa. So this seems to work. I will try the same for iClone.