I have had some success following a complaint direct to FTM2 for Mac. They have made a suggestion which I was sceptical about. They told me to change the date format in the MAC preferences from UK to USA. I immediately thought that my dates in FTM would go American but this is not the case. What effects this has on other MAC applications I have yet to see. Anyway a change and a full reboot didn't solve the issue and I told them so. What I did next was to download my Ancestry tree again into a new named FTM tree and from this point it has worked 100% after about 10 syncs. I still have the old FTM file just in case I have lost any data. The sync are now quite rapid rather than having to wait about 15 minutes so I am keeping my fingers crossed. It's worth a try. However David, you may well be in the USA so this might not be of much help!