Transfering from PC to Mac - Creative Cloud and Captivate 12/2019 - big issues!

Hi everyone - having enormous issues here. 

I have been using Captivate 2019 (11.5) plus trying out Captivate 12 (not 12.6) on my PC plus using Creative Cloud for a long time with no issues. 

The 2019 lilcense was when you used to install a demo and then activate - ie before the 12.8 CPc logo 

So everything is perfectly fine. Then my team moves me to a Mac. Creative Cloud installs fine. I install Captivate 2019 11.8 and it activates via the usual Adobe login + password. 

Then the issue - after a random amount of time, Captivate bombs out - shuts the program completely, loses any unsaved work and logs out of Adobe. The 2 Adobe login keys in the Access Keys app vanish. 

1) I am not logged into Captivate on any other machine

2) I log out of Creative Cloud on the PC

3) Still does this. No other Adobe application does this but once the Adobe account has logged out, obviously Creative Cloud won't work. 

Any help? Thanks