How to fix faulty 3dm file?

 From:  Brian (BWTR)
1604.12 In reply to 1604.11 
Thanks Michael.
At about 3am this morning I thought of something that may have been involved. Later today I will try and emulate that oringinal path and compare with your advice.
Busy day and its only 10 am. XP SP3, Carrara6.2 update---what next?