I think I spoke too soon in my last post. Having tried the software on several other machines, it turned out the greyed out head was still present.
After some contact with LEGO support, we still couldn’t figure out what was wrong. However, I did discover that the software did work properly on a different account on my MacBook. What was so different about that account? In the end I discovered it was because of some login scripts we had running on all the other Macs. This script moved and renamed the ~/Documents folder to trick the sidebar into defaulting the save location to the network home rather than locally. After changing this script so that ~/Documents was back in its default setting, everything seemed to work fine. Yay!