@ DUDU.car:

I use Carrara 8.1.1.12 oft and on and it is a very stable release. To me it is the last good known version of Carrara. I have reported some of the problems I had with 8.5.1.19 in this link.

Another problem I had was the incompatibility of projects created with 8.1.1.12 when opened in 8.5.x.x. For example in this link (Warning: image contains nudity) the hair for the girl on the left does not render in one of the 8.5.x.x releases and she is bald.

These are all very good reasons for me to stop using Carrara and switch to something else.