As regards A6 - I use it on multiple computers - but I am the only person who uses A6 - I think that's OK - sometimes I work at home and sometimes I work on the road, train etc, sometimes A6 seems to have problems on one machine, I like to try it on another sometimes. I think 3DGS says this is OK, have think this is reasonable usage. I do NOT share A6 with anyone else - I paid for it - why should i.
As regards 9c - I'm now not sure if it cuased the problem - I'll have to do some more research - but thanks for the feedback.